2.2. C++ Tutorials¶

This page follows the C++ tutorials “Up and Running with C++” by Peggy Fisher:

2.2.1. Print to Screen ¶

/*
File name: greetings.cpp
Date: 9 Dec 2016
Author: Andrew Roberts
*/

// to allow cin and cout:
#include <iostream>

// standard namespaces (avoids typing std:: cout etc):
using namespace std;

// main function:
int main()
{
	// screen output:
	cout << "Hello, and welcome to Up and Running with C++" << endl;

	// return zero:
	return 0;
}

2.2.2. Input and Output Values from Screen ¶

/*
File name: travel_cost.cpp
Date: 9 Dec 2016
Author: Andrew Roberts
*/

// to allow cin, cout, fixed:
#include <iostream>

// to allow setprecision:
#include <iomanip>

// standard namespaces:
using namespace std;

// main function:
int main()
{
	// variables:
	double mpg, distance, gallons, pricePerGallon, totalCost;

	// input mpg:
	cout << "Enter mpg" << endl;
	cin >> mpg;

	// input distance:
	cout << "Enter distance in miles: " << endl;
	cin >> distance;

	// input price per gallon:
	cout << "Enter price for one gallon of gas: " << endl;
	cin >> pricePerGallon;

	// calculate gallons needed:
	gallons = distance/mpg;

	// calculate total cost:
	totalCost = gallons * pricePerGallon;

	// output total cost to screen:
	// fixed point notation, with a precision of 2, e.g. 1000.00 not 1e3:
	cout << "Total trip cost: $" << fixed << setprecision(2) << totalCost << endl;

	return 0;
}

2.2.3. Data Types ¶

/*
File name: data_types.cpp
Date: 9 Dec 2016
Author: Andrew Roberts
*/

// allows cin, cout:
#include <iostream>

// standard namespaces:
using namespace std;

// main program:
int main()
{
	// parameters:
	char letter = 'a';
	short age = 10;
	int count = 575;
	long numStars = 985467528;
	float pi = 3.14;
	double price = 89.65;
	string season = "summer";

	// output:
	cout << "Letter: " << letter << endl;
	cout << "Age: " << age << endl;
	cout << "Count: " << count << endl;
	cout << "Number of stars in the sky: " << numStars << endl;
	cout << "Pi: " << pi << endl;
	cout << "Price: " << price << endl;
	cout << "Season: " << season << endl;

	// return integer:
	return 0;
}

2.2.4. Convert Numbers to Characters ¶

/*
File name: ascii_table.cpp
Date: 9 Dec 2016
Author: Andrew Roberts
*/

// cin, cout:
#include <iostream>

// standard namespaces:
using namespace std;

// main function:
int main()
{
	// declare temperature
	char character;

	// loop between 0 and 127
	for(int num = 0; num < 128; num++)
	{
		// set the number equal to the character:
		character = num;

		// output the number and character:
		cout << num << " : " << character << endl;
	}

	// return integer:
	return 0;
}

2.2.5. Static Casting ¶

/*
File name: dollars_and_cents.cpp
Date: 9 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>
#include <cmath>

using namespace std;

int main()
{

	// variables:
	int dollars, cents;
	double price, convert;

	// implicit conversion:
	char dollar_sign = 36;

	// input price:
	cout << "Enter price in dollars and cents: " << endl;
	cin >> price;

	// round down price to dollars:
	dollars = static_cast<int>(floor(price));

	// convert price to cents and round cents up:
	convert = price * 100 - static_cast<double>(dollars * 100);
	cents = static_cast<int>(ceil(convert));

	// output to screen:
	cout << "Total dollars: " << dollar_sign << dollars << " cents: " << cents << endl;

	return 0;

}

2.2.6. Expressions ¶

/*
File name: expressions.cpp
Date: 11 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>

using namespace std;

int main()
{
	// variables:
	int length, width, area, perimeter;
	int radius, circleArea, circumference;
	string firstName, lastName, fullName;

	// area and perimeter rectangle:
	cout<<"Enter the length and width of a rectangle"<<endl;
	cin>>length;
	cin>>width;
	area = length*width;
	perimeter = 2*length + 2*width;
	cout<<"The area of the rectangle is: "<<area<<endl;
	cout<<"The perimeter of the rectangle is: "<<perimeter<<endl;

	// area and circumference of circle:
	cout<<"Enter the radius of a circle:"<<endl;
	cin>>radius;
	circleArea = 3.14 * radius * radius;
	circumference = 2 * 3.14 * radius;
	cout<<"The area of the circle is: "<<circleArea<<endl;
	cout<<"The circumference of the circle is: "<<circumference<<endl;

	// add two strings:
	cout<<"Enter the first and last name"<<endl;
	cin>>firstName;
	cin>>lastName;
	fullName = firstName + " " +lastName;
	cout<<"The full name is: "<<fullName<<endl;
	return 0;

}

2.2.7. Conditional Statements ¶

/*
File name: shipping.cpp
Date: 11 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>
#include <iomanip>

using namespace std;

int main()
{
	double price, shipping;

	cout<<"enter the total price of the order: "<<endl;
	cin>>price;

	if(price > 75)
		shipping = 0;
	else if(price > 50)
		shipping = 5;
	else if(price > 25)
		shipping = 10;
	else if(price > 0)
		shipping = 15;

	cout<<"Total price including shipping is: "<<fixed<<setprecision(2)<<price + shipping<<endl;

	return 0;

}

2.2.8. While Loops ¶

/*
File name: loan.cpp
Date: 11 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>

using namespace std;

int main()
{
	int months = 0;
	double balance = 5000;
	double payment = 150;

	while(balance > 0)
	{
		months=months+1; 	//or months++;
		balance = balance - payment;	//or balance -= payment
	}
	cout<<"It will take you "<<months<<" months to pay off your loan"<<endl;

}

2.2.9. Do-While Loops ¶

/*
File name: membership.cpp
Date: 11 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>
#include <iomanip>

using namespace std;

int main()
{
	int menuChoice;
	int months;
	double totalCharges;

	//declare constant variables for membership costs
	const double ADULT = 40.0;
	const double CHILD = 30.0;
	const double FAMILY = 100.0;

	//setup the output formatting
	cout<<fixed<<setprecision(2)<<showpoint;

	do{
		//Print out the menu:
		cout<<"Please choose the type of membership"<<endl;
		cout<<"1. Adult Membership ($40/month)"<<endl;
		cout<<"2. Child Membership ($30/month)"<<endl;
		cout<<"3. Family Membership ($100/month)"<<endl;
		cout<<"4. Exit"<<endl;
		cin>>menuChoice;

		//validate the users menu choice using a while loop
		while(menuChoice < 1 || menuChoice > 4)
		{
			cout<<"Invalid choice, please re-enter menu item"<<endl;
			cin>>menuChoice;
		}

		if (menuChoice == 4)
			break;		//this allows us to exit our do/while loop

		//ask the user for duration in months of membership
		cout<<"Enter the number of months:"<<endl;
		cin>>months;

		//validate number of months
		while(months <1 || months > 24)
		{
			cout<<"Memberships must be between 1 month and 2 years (24 months), please enter a valid number"<<endl;
			cin>>months;
		}

		switch(menuChoice)
		{
		case 1:
			totalCharges = months * ADULT;
			break;
		case 2:
			totalCharges = months * CHILD;
			break;
		case 3:
			totalCharges = months * FAMILY;
			break;
		default:
			break;
		}

		cout<<"Based on your choice, your total charges will be $"<<totalCharges<<endl<<endl;

	} while(menuChoice != 4); 	//this allows the user to enter various membership options
	cout<<"Thanks for choosing our gym"<<endl;
	return 0;

}

2.2.10. For Loops ¶

/*
File name: print_odds.cpp
Date: 11 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>

using namespace std;

int main()
{
	for(int num = 1; num <= 100; num++)
	{
		if(num %2 != 0)
			cout<<num<<endl;
	}
	return 0;

}

2.2.11. Random Numbers 1 ¶

/*
File name: random.cpp
Date: 14 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;
int main()
{
	srand(time(0));
	for(int i = 0;i<10;i++)
	{
		cout<<rand()<<endl;
	}
	return 0;
}

2.2.12. Random Numbers 2 ¶

/*
File name: snake_eyes.cpp
Date: 14 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>
#include <cstdlib>
#include <ctime>
#include <iomanip>
using namespace std;
int main()
{
	srand(time(0));
	int count = 0;
	for (int i = 0;i<100;i++)
	{
		int die1 = rand()%6 + 1;
		int die2 = rand()%6 + 1;
		cout<<setw(6)<<die1<<setw(6)<<die2;
		if(die1 == 1 && die2 == 1)
		{
			cout<<"  Snake Eyes";
			count ++;
		}
		cout<<endl;
	}
	cout<<"There were "<<count<<" snake eyes"<<endl;
}

2.2.13. User Defined Functions 1 ¶

/*
File name: distance.cpp
Date: 16 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>
#include <cmath>
using namespace std;

double getDistance(int x1, int y1, int x2, int y2)
{
	double distance;
	distance = sqrt(pow((x2-x1),2) + pow((y2 - y1), 2));
	return distance;
}

int main()
{
	int x1, x2, y1, y2;

	cout<<"Please enter the first point x1, then y1"<<endl;
	cin>>x1;
	cin>>y1;

	cout<<"Now enter the second point"<<endl;
	cin>>x2;
	cin>>y2;

	cout<<"The distance between these two points is: "<<
			getDistance(x1,y1,x2,y2)<<endl;

	return 0;
}

2.2.14. User Defined Functions 2 ¶

/*
File name: bool_function.cpp
Date: 16 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;

/*
 * display a message
 */
int number;
bool guess(int);

int main()
{
	int usernum;
	srand(time(0));
	number = rand() % 50 + 1;
	cout<<"Guess a number between 1 and 50:"<<endl;
	cin>>usernum;
	while(guess(usernum) != true)
	{
		cout<<"Try again:"<<endl;
		cin>>usernum;
	}
	cout<<"You guessed it!!! "<<endl;
	return 0;
}
bool guess(int num)
{
	if(num == number)
		return true;
	if(num > number)
		cout<<"Too high"<<endl;
	else
		cout<<"Too low"<<endl;
	return false;
}

2.2.15. Call by Value ¶

/*
File name: call_by_value.cpp
Date: 16 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>
using namespace std;

/*
 * this function adds 5 to a and b temporarily since they are call by value arguments
 * @param int a, int b
 */
void addfive(int a, int b)
{
	cout<<"entering addfive function"<<endl;
	cout<<"a and b before adding 5: a="<<a<<" b="<<b<<endl<<endl;
	a += 5;
	b += 5;
	cout<<"a and b after adding 5: a="<<a<<" b="<<b<<endl;
	cout<<"leaving addfive function"<<endl<<endl;
}
int main()
{
	int a = 10, b = 15;
	cout<<"a and b before calling addfive function: a="<<a<<" b="<<b<<endl<<endl;

	addfive(a,b);

	cout<<"a and b after calling addfive function: a="<<a<<" b="<<b<<endl;
	return 0;


}

2.2.16. Call by Reference ¶

/*
File name: call_by_reference.cpp
Date: 16 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>
using namespace std;
/*
 * this function adds 5 to a and b temporarily since they are call by value arguments
 * @param int a, int b
 */
void addfive(int& a, int& b)
{
	cout<<"entering addfive function"<<endl;
	cout<<"a and b before adding 5: a="<<a<<" b="<<b<<endl<<endl;
	a += 5;
	b += 5;
	cout<<"a and b after adding 5: a="<<a<<" b="<<b<<endl;
	cout<<"leaving addfive function"<<endl<<endl;
}
int main()
{
	int a = 10, b = 15;
	cout<<"a and b before calling addfive function: a="<<a<<" b="<<b<<endl<<endl;
	addfive(a,b);
	cout<<"a and b after calling addfive function: a="<<a<<" b="<<b<<endl;
	return 0;


}

2.2.17. Default Arguments ¶

/*
File name: default_arguments.cpp
Date: 16 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>
using namespace std;
/*
 * This function calculates the perimeter of any rectangle
 * @param length, width
 */
int findPerimeter(int length = 20, int width = 30);

int main()
{
	//call function with no arguments
	int p = findPerimeter();
	cout<<"perimeter value for findPerimeter() call: "<<p<<endl;

	//call function with two arguments
	p = findPerimeter(5,10);
	cout<<"perimeter value for findPerimeter(5,10) call: "<<p<<endl;

	//call function with only one argument
	p = findPerimeter(10);
	cout<<"perimeter value for findPerimeter(10) call: "<<p<<endl;

	return 0;
}

int findPerimeter(int length, int width)
{
	return 2*length + 2 * width;
}

2.2.18. Function Overloading ¶

/*
File name: hospital_stay.cpp
Date: 16 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>
using namespace std;

double calculateCharges(int, double, double, double);
double calculateCharges(double, double);

int main()
{
	int days;
	double dailyRate, medCharges, labCharges, totalDue;
	bool inpatient = false;
	char answer;

	cout<<"Is this an inpatient stay?"<<endl;
	cin>>answer;
	while(answer != 'y' && answer != 'n')
	{
		cout<<"Please enter y/n"<<endl;
		cin>>answer;
	}
	if(answer == 'y')
		inpatient = true;
	else
		inpatient = false;

	cout<<"Enter the total medication charges: "<<endl;
	cin>>medCharges;
	cout<<"Enter the total lab charges: "<<endl;
	cin>>labCharges;

	if(inpatient == true)
	{
		cout<<"please enter days spent in the hospital: "<<endl;
		cin>>days;
		cout<<"please enter the daily rate: "<<endl;
		cin>>dailyRate;

		//call the function that takes 4 parameters
		totalDue = calculateCharges(days, dailyRate,
				medCharges, labCharges);
	}
	else
	{
		//call the function that takes 2 parameters
		totalDue = calculateCharges(medCharges, labCharges);
	}

	cout<<"The total cost is: $"<<totalDue<<endl;
	return 0;
}

double calculateCharges(int d, double r, double m, double l)
{
	return d*r+m+l;
}
double calculateCharges(double m, double l)
{
	return m+l;
}

2.2.19. Challenge (Call by Reference)¶

/*
File name: challenge_change.cpp
Date: 16 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>
#include <iomanip>
#include <cmath>

using namespace std;

// function prototypes
void get_items(string&);
void get_price_and_paid(int&, int&, int&, int&);
void set_change(int&, int, int, int, int);
void set_coins(int&, int&, int&, int&, int&, int&);
void print_coins(int&, int&, int&, int&, int&, int&);

int main()
{
	int price_dollars, price_cents, paid_dollars, paid_cents;
	int dollars, quarters, dimes, nickels, pennies;
	string items;
	int change = 0; // initialises change to zero

	cout << "-----------------------" << endl;
	cout << "Welcome to the store!!!" << endl;
	cout << "-----------------------" << endl;

	get_items(items);

	while (items == "y")
	{
		get_price_and_paid(price_dollars, price_cents, paid_dollars, paid_cents);
		set_change(change, price_dollars, price_cents, paid_dollars, paid_cents);

		while (change < 0)
		{
			cout << "I'm sorry, the price is wrong, or the customer has not paid the full amount!" << endl;
			get_price_and_paid(price_dollars, price_cents, paid_dollars, paid_cents);
			set_change(change, price_dollars, price_cents, paid_dollars, paid_cents);
		}

		set_coins(change, dollars, quarters, dimes, nickels, pennies);
		print_coins(change, dollars, quarters, dimes, nickels, pennies);
		get_items(items);
	}

	cout << "-------------------------------" << endl;
	cout << "Thank you, please come again!!!" << endl;
	cout << "-------------------------------" << endl;
	return 0;
}

void get_items(string& items)
{
	cout << "Do you have any items to pay for? (y or n):" << endl;
	cin >> items;

	while (items != "y" && items != "n")
	{
		cout << "I'm sorry, please enter y or n if you have items:" << endl;
		cin >> items;
	}
}

void get_price_and_paid(int& price_dollars, int& price_cents, int& paid_dollars, int& paid_cents)
{
	cout << "Please enter the price of the item (in dollars): " << endl;
	cin >> price_dollars;
	cout << "Please enter the price of the item (in cents): " << endl;
	cin >> price_cents;
	cout << "Please enter the amount the customer paid (in dollars):" << endl;
	cin >> paid_dollars;
	cout << "Please enter the amount the customer paid (in cents):" << endl;
	cin >> paid_cents;
}

void set_change(int& change, int price_dollars, int price_cents, int paid_dollars, int paid_cents)
{
	change = 100*(paid_dollars-price_dollars) + (paid_cents-price_cents);
}

void set_coins(int& change, int& dollars, int& quarters, int& dimes, int& nickels, int& pennies)
{
	cout << "The change in pennies is: " << change << endl;
	dollars = change / 100;
	quarters = (change % 100) / 25;
	dimes = (change % 100 % 25) / 10;
	nickels = (change % 100 % 25 % 10) / 5;
	pennies = (change % 100 % 25 % 10 % 5) / 1;
	change = change - (dollars * 100) - (quarters * 25) - (dimes * 10) - (nickels * 5) - (pennies * 1);
}

void print_coins(int& change, int& dollars, int& quarters, int& dimes, int& nickels, int& pennies)
{
	cout << "The number of dollars in the change is: " << dollars << endl;
	cout << "The number of quarters in the change is: " << quarters << endl;
	cout << "The number of dimes in the change is: " << dimes << endl;
	cout << "The number of nickels in the change is: " << nickels << endl;
	cout << "The number of pennies in the change is: " << pennies << endl;
	cout << "The change in pennies is now: " << change << endl;
}

2.2.20. Classes, Header File ¶

/*
File name: House.h
Date: 17 Dec 2016
Author: Andrew Roberts
*/

#ifndef HOUSE_H_
#define HOUSE_H_
#include <string>
using namespace std;

class House {
private:
	string houseColor;
	int numBathrooms;
	int numBedrooms;
	double squareFeet;

public:
	//constructors
	House();
	House(string, int, int, double);

	//destructor
	~House();

	//accessor methods
	string getColor();
	int getNumBath();
	int getNumBed();
	double getSqft();

	//mutator methods
	void setColor(string);
	void setNumBath(int);
	void setNumBed(int);
	void setSqft(double);
};

#endif /* HOUSE_H_ */

2.2.21. Classes, Body of Header File ¶

/*
File name: House.cpp
Date: 17 Dec 2016
Author: Andrew Roberts
*/

#include "House.h"
#include <iostream>
using namespace std;

	//default constructor
	House::House()
	{
		houseColor = "Blue";
		numBathrooms = 2;
		numBedrooms = 3;
		squareFeet = 1200;
	}
	House::House(string color, int numBath, int numBed, double sqft)
	{
		houseColor = color;
		numBathrooms = numBath;
		numBedrooms = numBed;
		squareFeet = sqft;

	}
	//destructor method
	House::~House()
	{
		//cout<<"I'm in the destructor"<<endl;
	}

	//accessor methods
	string House::getColor()
	{
		return houseColor;
	}
	int House::getNumBath()
	{
		return numBathrooms;
	}
	int House::getNumBed()
	{
		return numBedrooms;
	}
	double House::getSqft()
	{
		return squareFeet;
	}

	//mutator methods
	void House::setColor(string c)
	{
		houseColor = c;
	}
	void House::setNumBath(int bath)
	{
		numBathrooms = bath;
	}
	void House::setNumBed(int bed)
	{
		numBedrooms = bed;
	}
	void House::setSqft(double sqft)
	{
		squareFeet = sqft;
	}

2.2.22. Classes, Main Function, Instantiation ¶

/*
File name: houses.cpp
Date: 17 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>
#include "House.h"
#include <string>
using namespace std;

void printHouse(House);

int main()
{
	//Create an instance of the House class
	//using the default constructor
	House house1;

	//Create a second instance
	//provide values for color, bed, bath, and sqft
	House house2("Tan", 3, 2, 2500);

	//print house information
	printHouse(house1);
	printHouse(house2);
	house2.setColor("White");
	house2.setNumBath(3);
	house2.setNumBed(4);
	house2.setSqft(3500);
	printHouse(house2);

	return 0;
}
void printHouse(House house)
{
	//print the house information using
	//the dot operator
	cout<<"House Color: "<<house.getColor()
			<<"\nNumber Bathrooms: "
			<<house.getNumBath()
			<<"\nNumberBedrooms: "
			<<house.getNumBed()<<endl;
	cout<<"Total Square feet: "
			<<house.getSqft()<<endl;
	cout<<endl<<endl;

	//since it is a void function,
	//I do not need a return statement
}

2.2.23. Challenge (Classes), Header File ¶

/*
File name: Movie.h
Date: 18 Dec 2016
Author: Andrew Roberts
*/

#ifndef MOVIE_H_
#define MOVIE_H_

#include <string>

using namespace std;

class Movie
{
	private:
		string name;
		int year;
		string rating;

	public:
		// constructors
		Movie();
		Movie(string, int, string);

		// destructor
		~Movie();

		string get_name();
		int get_year();
		string get_rating();

		void set_name(string);
		void set_year(int);
		void set_rating(string);
};

#endif /* MOVIE_H_ */

2.2.24. Challenge (Classes), Body of Header File ¶

/*
File name: Movie.cpp
Date: 18 Dec 2016
Author: Andrew Roberts
*/

#include "Movie.h"
#include <iostream>

using namespace std;

// default constructor:
Movie::Movie()
{
	name = "Star Wars";
	year = 1977;
	rating = "PG";
}

// constructor:
Movie::Movie(string name, int year, string rating)
{
	this->name = name;
	this->year = year;
	this->rating = rating;
}

// destructor:
Movie::~Movie()
{

}

// accessor methods

string Movie::get_name()
{
	return name;
}

int Movie::get_year()
{
	return year;
}

string Movie::get_rating()
{
	return rating;
}

// mutator methods

void Movie::set_name(string name)
{
	this->name = name;
}

void Movie::set_year(int year)
{
	while(year < 1950 || year > 2016)
	{
		cout << "Sorry, please enter movie year between 1950 and 2016: ";
		cin >> year;
		cin.ignore(); // needed so the getline function does not use the return as input
	}
	this->year = year;
}

void Movie::set_rating(string rating)
{
	this->rating = rating;
}

2.2.25. Challenge (Classes), Main Function ¶

/*
File name: movies.cpp
Date: 18 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>
#include "Movie.h"
#include <string>
#include <cctype>
using namespace std;

void print_movie(Movie);
void set_movie(Movie&);

int main()
{
	cout << "Please enter your three favourite movies: " << endl;

	Movie movie_one;
	set_movie(movie_one);
	Movie movie_two;
	set_movie(movie_two);
	Movie movie_three;
	set_movie(movie_three);

	print_movie(movie_one);
	print_movie(movie_two);
	print_movie(movie_three);

	return 0;
}

void print_movie(Movie movie)
{
	cout << "Movie name: " << movie.get_name() << endl;
	cout << "Movie year: " << movie.get_year() << endl;
	cout << "Movie rating: " << movie.get_rating() << endl;
	cout << "" << endl;
}

void set_movie(Movie& new_movie)
{
	string new_name;
	int new_year;
	string new_rating;

	cout << "Enter movie name: ";
	getline(cin, new_name);
	new_movie.set_name(new_name);

	cout << "Enter movie year: ";
	cin >> new_year;
	cin.ignore(); // needed so the getline function does not use the return as input
	new_movie.set_year(new_year);

	cout << "Enter movie rating: ";
	getline(cin, new_rating);
	new_movie.set_rating(new_rating);

	cout << "" << endl;
}

2.2.26. Arrays 1 ¶

/*
File name: arrays.cpp
Date: 21 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>
#include <string>
#include <cstdlib>
using namespace std;

int main()
{
	//array declarations
	string seasons[4];
	int numbers[10];
	for(int i = 0;i<10;i++)
	{
		numbers[i] = rand();
	}

	//declare and initialize the array
	string weekdays[] = {"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"};

	//change the value of an array
	seasons[0] = "summer";
	seasons[1] = "fall";
	seasons[2] = "winter";
	seasons[3] = "spring";

	cout<<seasons<<endl;
	cout<<seasons[0]<<endl;
	cout<<seasons[1]<<endl;
	cout<<seasons[2]<<endl;
	cout<<seasons[3]<<endl;

	cout<<numbers[0]<<endl;
	return 0;
}

2.2.27. Arrays 2 ¶

/*
File name: heights.cpp
Date: 21 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>
#include <string>
using namespace std;

void getWeights(double[], int);
double findAverage(double[], int);
double findHeaviest(double[], int);

int main()
{
	double weights[10];
	getWeights(weights, 10);
	cout<<"The average weight of all students is: "
			<<findAverage(weights, 10)<<" pounds"<<endl;
	cout<<"The heaviest student is: "
				<<findHeaviest(weights, 10)<<" pounds"<<endl;

	return 0;
}
void getWeights(double h[], int size)
{
	for(int i = 0; i<size; i++)
	{
		cout<<"Enter student weight in pounds: \n";
		cin>>h[i];
	}
}
double findAverage(double h[], int size)
{
	int count = 0;
	double total = 0;
	for(int i = 0; i<size; i++)
		{
			count++;
			total += h[i];
		}
	return total/count;
}
double findHeaviest(double h[], int size)
{
	double heaviest = h[0];
	for(int i = 1; i<size; i++)
	{
		if(h[i] > heaviest)
		{
			heaviest = h[i];
		}
	}
	return heaviest;
}

2.2.28. Abstract Data Types ¶

/*
File name: employees.cpp
Date: 23 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>

using namespace std;

//define the new data structure
struct Address
{
	char houseNum[5];
	char streetName[30];
	char city[30];
	char state[3];
	int zipcode;
};
struct DateOfBirth
{
	int month;
	int day;
	int year;

};
struct Employee
{
	char firstName[30];
	char lastName[30];
	int eeNumber;
	double hourlyWage;
	Address homeAddress;
	DateOfBirth dob;
};
//printEes prototype
void printEes(Employee[],int);

int main()
{
	int numEmployees;
	cout<<"How many employees do you have? \n";
	cin>>numEmployees;
	//create an array of type Employee
	Employee employees[numEmployees];

	//loop for creating new employee data structure variables
	for(int i = 0;i < numEmployees;i++)
	{
		cout<<"Please enter first name: \n";
		cin>>employees[i].firstName;
		cout<<"Enter last name: \n";
		cin>>employees[i].lastName;
		cout<<"Enter employee id: \n";
		cin>>employees[i].eeNumber;
		cout<<"Enter hourly wage: \n";
		cin>>employees[i].hourlyWage;
		cout<<"Enter house number: \n";
		cin>>employees[i].homeAddress.houseNum;
		cin.ignore();
		cout<<"Enter street name: \n";
		cin.getline(employees[i].homeAddress.streetName, 30);
		cout<<"Enter city: \n";
		cin>>employees[i].homeAddress.city;
		cout<<"Enter state: \n";
		cin>>employees[i].homeAddress.state;
		cout<<"Enter zipcode: \n";
		cin>>employees[i].homeAddress.zipcode;
		cout<<"Enter birth month, day and year:  \n";
		cin>>employees[i].dob.month;
		cin>>employees[i].dob.day;
		cin>>employees[i].dob.year;
	}

	printEes(employees,numEmployees);
}

void printEes(Employee employees[], int size)
{
	for(int i = 0; i < size; i++)
	{
		cout<<employees[i].firstName <<" "
				<<employees[i].lastName<<endl;
		cout<<employees[i].homeAddress.houseNum<<" "
				<<employees[i].homeAddress.streetName<<endl;
		cout<<employees[i].homeAddress.city<<", "
				<<employees[i].homeAddress.state<<" "
				<<employees[i].homeAddress.zipcode<<endl;
		cout<<"Hourly wage: "<<employees[i].hourlyWage;
		cout<<endl;
		cout<<"Date of Birth: ";
		switch(employees[i].dob.month)
		{
		case 1:
			cout<<"January ";
			break;
		case 2:
			cout<<"February ";
			break;
		case 3:
			cout<<"March ";
			break;
		case 4:
			cout<<"April ";
			break;
		case 5:
			cout<<"May ";
			break;
		case 6:
			cout<<"June ";
			break;
		case 7:
			cout<<"July ";
			break;
		case 8:
			cout<<"August ";
			break;
		case 9:
			cout<<"September ";
			break;
		case 10:
			cout<<"October ";
			break;
		case 11:
			cout<<"November ";
			break;
		case 12:
			cout<<"December ";
			break;
		default:
			cout<<"Invalid Month";
			break;
		};
		cout<<employees[i].dob.day<<", ";
		cout<<employees[i].dob.year<<endl;
	}
}

2.2.29. Pointers ¶

/*
File name: pointers.cpp
Date: 24 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>

using namespace std;

int main()
{
/*
	int JohnsAcct = 12345;
	int* acctPtr = &JohnsAcct;

	cout<<"Johns acct number: "<<JohnsAcct<<" is at: "<<acctPtr<<endl;
	cout<<"acctPtr points to this value: *acctPtr:"<<*acctPtr<<endl;
*/
	//another example
	cout<<endl<<"Next example, declares num = 95:"<<endl;
	int num = 95;
	cout<<"Address to find num value: "<<&num<<endl;
	cout<<"size of num value based on datatype: "<<sizeof(num)<<endl;
	cout<<"value at this location: "<<num<<endl;

	cout<<endl<<"Next example, add numPtr:"<<endl;
	//lets add a pointer to hold the address of num
	int* numPtr = &num;

	//lets change the value of num using the pointer
	cout<<"add 5 to num using the pointer and not the variable:"<<endl;
	*numPtr += 5;  //num value is now 100
	cout<<"Num is now: "<<num<<endl;
	cout<<"Num location is still the same: "<<&num<<endl;
	cout<<"Location of numPtr is: "<<numPtr<<endl;
	cout<<"Value of numPtr is: "<<*numPtr<<endl;

	cout<<endl<<"Next example, using characters"<<endl;
	char letter = 'A';
	cout<<"size of letter value based on datatype: "<<
			sizeof(letter)<<endl;
	cout<<"value at this location: "<<letter<<endl;
	//lets add a pointer to hold the address of letter
	char* letterPtr = &letter;

	//lets change the value of letter using the pointer
	cout<<"\nadd 25 to letter:"<<endl;
	*letterPtr += 25;  //letter value is now Z
	cout<<"Letter is now: "<<letter<<endl;

	return 0;
}

2.2.30. Vectors ¶

/*
File name: vectors.cpp
Date: 24 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>
#include <vector>
#include <cstdlib>
using namespace std;

int main()
{
	//create three vectors
	//carVins contains the vin of each car on a showroom floor
	//(note: carVins starts as an empty vector)
	vector<int> carVins;

	//num contains 10 integer values
	vector<int> num(10);

	//prices contains 5 prices that are initially zero
	vector<double> prices(5,0.0);

	int numCars;
	int vin;

	cout<<"How many cars are in the showroom?\n";
	cin>>numCars;
	for(int i = 0; i<numCars; i++)
	{
		cout<<"Enter the vin for car "<<i+1<<" :";
		cin>>vin;
		//add the new vin to the end of the vector
		carVins.push_back(vin);
	}

	//print the vins:
	cout<<"\nVin numbers for cars in showroom:\n";
	for(int i = 0; i<carVins.size();i++)
	{
		cout<<carVins[i]<<endl;
	}

	//add 10 random integers to the num vector
	int randomNum;
	for(int i = 0; i < num.size(); i++)
	{
		num[i] = rand();
	}

	//print the random numbers:
	cout<<"\n10 random integers: \n";
	for(int i = 0; i<num.size();i++)
	{
		cout<<num[i]<<endl;
	}

	//Other vector functions include:
	//.at returns the value located at element 0
	int value = num.at(0);

	//.capacity() returns the max number of elements
	//that may be stored
	//without adding additional memory
	int value2 = num.capacity();

	//.pop_back removes the last element from a vector
	num.pop_back();

	//.clear() is used to clear a vector of all elements
	num.clear();

	//.empty() returns true if vector is empty
	if(num.empty()==true)
		cout<<"vector num is empty\n";

	//.swap(vector2) swaps the contents

}

2.2.31. Sorting, Binary Search ¶

/*
File name: binary_search.cpp
Date: 24 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>
#include <ctime>
#include <cstdlib>
using namespace std;

bool search(int[], int, int);

int main()
{
	srand(time(0));
	int nums[10];
	for(int i = 0;i<10;i++)
	{
		nums[i] = rand()%100 + 1;
	}
	cout<<"Array before sort"<<endl;
		for(int i = 0; i<10;i++)
			cout<<nums[i]<<" ";
		cout<<endl;

	//sort the array using a selection sort
	for(int j=0; j<10; j++)
	{
		int index = j;
		for(int k=j; k<10; k++)
		{
			if(nums[index]>nums[k])
			{
				index = k;
			}
		}
		int temp = nums[j];
		nums[j] = nums[index];
		nums[index] = temp;
	}
	cout<<"Array after sort"<<endl;
	for(int i = 0; i<10;i++)
		cout<<nums[i]<<" ";
	cout<<endl;

	int value;
		cout<<"Enter a number between 1 and 100: "<<endl;
		cin>>value;

	if(search(nums, 10, value)== true)
	{
		cout<<"Value "<<value<<" was found\n";
	}
	else
	{
		cout<<"Value "<<value<<" was not found\n";
	}
}
bool search(int numbers[], int size, int value)
{
	//to use a binary search, the array must
	//already be in sorted order
	bool found = false;
	int low = 0;
	int high = size - 1;
	int pos = 0;
	while(low <= high && !found)
	{
		pos = (low + high)/2;
		if(numbers[pos] == value)
		{
			found = true;
		}
		else if(numbers[pos] < value)
			{
				low = pos+1;
			}
			else
			{
				high = pos - 1;
			}
	}
	return found;
}

2.2.32. Challenge (Search)¶

/*
File name: challenge_lunch_menu.cpp
Date: 24 Dec 2016
Author: Andrew Roberts
*/

#include <iostream>
#include <string>
//#include <algorithm>
#include <vector>
// to allow setprecision:
#include <iomanip>
using namespace std;

//int findNumber(string array[], int size, string target);

int search(string[], int, string);
void print_total_cost(int[], double[], int[], double);
void get_choices(int, string[], int[], int, string[]);
void get_quantities(int, string[], int[]);

int main()
{
	string menu[] = {"hotdog", "hamburger", "french fries", "salad", "exit"};
	double prices[] = {1.20, 3.34, 0.99, 1.11, 0.00};
	string choices[] = {"exit", "exit", "exit", "exit"};
	int quantities[] = {0, 0, 0, 0};
	int positions[] = {4, 4, 4, 4};
	int arraysize = 5;
	double cost = 0.0;

	for(int i=0; i<4; i++)
	{
		get_choices(i, choices, positions, arraysize, menu);

		while(positions[i] == -1)
		{
			cout << "Invalid choice." << endl;
			get_choices(i, choices, positions, arraysize, menu);
		}

		if (choices[i].compare("exit") == 0)
		{
			break;
		}

		get_quantities(i, choices, quantities);
	}

	print_total_cost(quantities, prices, positions, cost);

	return 0;

}

void get_choices(int i, string choices[], int positions[], int arraysize, string menu[])
{
	cout << "Please enter choice number " << i+1 << " (hotdog, hamburger, french fries, salad or exit)." << endl;
	getline(cin, choices[i]);
	positions[i] = search(menu, arraysize, choices[i]);
}

void get_quantities(int i, string choices[], int quantities[])
{
	cout << "Please enter quantity of " << choices[i] << endl;
	cin >> quantities[i];
	cin.ignore();
}

void print_total_cost(int quantities[], double prices[], int positions[], double cost)
{
	cout << "This is the total cost:" << endl;
	for(int i=0; i<4; i++)
	{
		cost += quantities[i]*prices[positions[i]];
	}
	cout << "$" << fixed << setprecision(2) << cost << endl;
}

int search(string numbers[], int size, string value)
{

	bool exit = false;
	int pos = 0;
	while(!exit)
	{
		if(numbers[pos] == value)
		{
			exit = true;
		}
		else if(pos + 1 == size)
		{
			pos = -1;
			exit = true;
		}
		else
		{
			pos = pos + 1;
		}
	}
	return pos;
}

2.2.33. File Operations 1 ¶

/*
File name: fortune_teller.cpp
Date: 13 Jan 2017
Author: Andrew Roberts
*/

#include <iostream>
#include <cstdlib>
#include <cstring>
#include <fstream> // reading, writing and creating files
#include <ctime>
using namespace std;

string getRandomReply(string [], int);

int main()
{
	ifstream inputfile;
	//declare an input file
	inputfile.open("replies.txt", ios::in);

	char answer[30];
	string answers[20];
	int pos = 0;

	//read from the file until end of file (eof)
	while(!inputfile.eof())
	{
		inputfile.getline(answer, 30);
		answers[pos] = answer;
		pos ++;
	}

	cout<<"Think of a question for the fortune teller, "
			"\npress enter for the answer "<<endl;
	cin.ignore();
	cout<<getRandomReply(answers,20)<<endl;

}
string getRandomReply(string replies[],int size)
{
	srand(time(0));
	int randomNum = rand()%20;
	return replies[randomNum];
}

2.2.34. File Operations 2 ¶

/*
File name: mailing_addresses.cpp
Date: 13 Jan 2017
Author: Andrew Roberts
*/

#include <iostream>
#include <fstream>
using namespace std;

//create a new datatype for holding addresses
struct Address
{
	string fullName;
	char houseNum[5];
	char streetName[30];
	char city[30];
	char state[3];
	int zipcode;
};

void writeToFile(Address m[], int size);

int main()
{
	int numees;
	string fullname;
	string fname, lname;
	cout<<"How many employees do you have? \n";
	cin>>numees;
	Address mailing[numees];

	for(int i = 0;i < numees;i++)
	{
		cout<<"Please enter first name: \n";
		cin>>fname;
		cout<<"Enter last name: \n";
		cin>>lname;
		fullname = fname + " " + lname;
		mailing[i].fullName = fullname;
		cout<<"Enter house number: \n";
		cin>>mailing[i].houseNum;
		cin.ignore();
		cout<<"Enter street name: \n";
		cin.getline(mailing[i].streetName, 30);
		cout<<"Enter city: \n";
		cin>>mailing[i].city;
		cout<<"Enter state: \n";
		cin>>mailing[i].state;
		cout<<"Enter zipcode: \n";
		cin>>mailing[i].zipcode;
	}

	writeToFile(mailing,numees);

}

void writeToFile(Address m[], int size)
{
	ofstream output;
	output.open("mailingaddress.txt", ios::out);
	for(int i = 0; i < size; i++)
	{
		output<<m[i].fullName<<endl;
		output<<m[i].houseNum<<" "<<m[i].streetName<<endl;
		output<<m[i].city<<", "<<m[i].state<<" " <<m[i].zipcode<<endl;
		output<<endl;

	}
}

2.2.35. Error Handling ¶

/*
File name: error_handling.cpp
Date: 13 Jan 2017
Author: Andrew Roberts
*/

#include <iostream>
using namespace std;
int main()
{
	int errorcode= 10;
	int numerator;
	int denominator;
	do{
	cout<<"Enter numerator: ";
	cin>>numerator;
	cout<<"Enter denominator: ";
	cin>>denominator;
	try
	{
		if(denominator == 0)
			throw errorcode;
		else
			cout<<"The ratio is: "<<numerator/denominator<<endl;
	}
	catch(int error)
	{
		if(error == errorcode)
		{
			cout<<"\nDivide by zero error!! \n ";
		}
	}
	}while(denominator != 0);
return 0;
}

2.2.36. Challenge (Error Handling and File Operations)¶

/*
File name: challenge_file_read.cpp
Date: 14 Jan 2017
Author: Andrew Roberts
*/

#include <iostream>
#include <fstream> // reading, writing and creating files
#include <iomanip> // setprecision
#include <vector>
#include <stdlib.h>
#include <numeric>
using namespace std;

int add_columns(vector<int>, vector<int>);
double average_column(vector<int>);
int error_code=666;

int main()
{
	ifstream inputfile;
	try
	{
		inputfile.open("numbers.txt", ios::in);
		if(inputfile.fail())
		{
			throw error_code;
		}
	}
	catch(int error_number)
	{
		if(error_number==error_code)
		{
			cout << "File reading error." << endl;
			exit(1);
		}
	}

	int number_1;
	int number_2;
	vector<int> column_1;
	vector<int> column_2;

	while(!inputfile.eof())
	{
		inputfile >> number_1;
		column_1.push_back(number_1);
		inputfile >> number_2;
		column_2.push_back(number_2);
	}

	int total = add_columns(column_1, column_2);
	cout << "Total: " << total << endl;

	double average_1 = average_column(column_1);
	cout << "Average column 1: " << fixed << setprecision(2) << average_1 << endl;

	double average_2 = average_column(column_2);
	cout << "Average column 2: " << fixed << setprecision(2) << average_2 << endl;
}

int add_columns(vector<int> column_1, vector<int> column_2)
{
	double total_1 = accumulate(column_1.begin(), column_1.end(), 0.0);
	double total_2 = accumulate(column_2.begin(), column_2.end(), 0.0);
	return total_1+total_2;
}

double average_column(vector<int> column_1)
{
	double average = accumulate(column_1.begin(), column_1.end(), 0.0)/column_1.size();
	return average;
}

2.2.37. Challenge - Simple (Error Handling and File Operations)¶

/*
File name: challenge_file_read_simple.cpp
Date: 16 Jan 2017
Author: Andrew Roberts
*/


#include <iostream>
#include <fstream> // reading, writing and creating files

#include <stdlib.h> // exit

using namespace std;

double column_1 = 0.0;
double column_2 = 0.0;
double column_1_total = 0.0;
double column_2_total = 0.0;
int count = 0;

int error_signal=666;

int main()
{
	ifstream inputfile;
	try
	{
		inputfile.open("numbers.txt", ios::in);
		if(inputfile.fail())
		{
			throw error_signal;
		}
	}
	catch(int error_number)
	{
		if(error_number==error_signal)
		{
			cout << "File reading error." << endl;
			exit(1);
		}
	}

	while(!inputfile.eof())
	{
		inputfile >> column_1;
		column_1_total += column_1;
		inputfile >> column_2;
		column_2_total += column_2;
		count++;
	}

	cout << "Average of column 1: " << column_1_total/count << endl;
	cout << "Average of column 2: " << column_2_total/count << endl;

}