C++, C, and C#

Objective #1: Create a simple hello world program in C++

C++ was created in the early 1980's by Bjarne Stroustrup. He took the language C and added classes to it. C++ is object-oriented though it does not require a program to be created with classes like Java does. C++ is a great all-around programming language suitable for many different types of applications (business, engineering, games, operating systems, etc.)
Click the menu command Start/All Programs/Microsoft Visual Studio .NET 2003/Microsoft Visual Studio .NET 2003 to open MS Visual Studio. With Visual Studio, you can create a C++ project. Like Eclipse, Visual Studio is a very popular IDE that is used by many professional programmers. In fact, the VB IDE that we used in our Visual Basic course is part of the full Visual Studio environment.
Click the menu command File/New Project to create a project. Click Visual C++ Projects under "Project Types" in the left panel. Select the "Empty Project (.NET)" icon under "Templates" in the right panel. Type the name "CplusplusHelloWorld" (I don't like using the symbols ++ in a filename) and verify that the Location is your student network folder. Then click the OK button.
Click the menu command Project/Add New Item. Click the "C++ File (.cpp)" icon under "Templates" in the right panel. Type the name "CplusplusHelloWorld.cpp" for Name and click the Open button.
Type the following code:

#include <iostream>
using namespace std;

void main()
{
cout << "hello world" << endl;
}
Click the menu command Build/Compile to compile the program and check for errors. Errors are listed in the Output window in the lower pane.
Click the menu command Debug/Start Without Debugging to execute the program.
Here is a more complicated example that allows for user input and that includes a function.

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

int add(int x, double y)
{
   return x + y;
}

void main()
{
   int a = 0;
   double b = 0;
   string name;
   double answer = 0;
   cout << "Enter your name, an integer, and a decimal value: ";
   cin >> name;
   cin >> a;
   cin >> b;
   answer = add(a, b);
   cout << name << ", the answer is " << answer << endl;
}

Here is a more complicated example that uses a class.

	


#ifndef CUBE_H
#define CUBE_H

class Cube
{
public:
	Cube();
	~Cube();
	void setSide(double s);
	double getSide();
	double area();
	double volume();
	void toString();
private:
	double side;
};

#endif

//Source File cube.cpp

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

// constructor
Cube::Cube()
{
}

// destructor
Cube::~Cube()
{
}

void Cube::setSide(double s)
{
	side = s <= 0 ? 1 : s;
}

double Cube::getSide()
{
	return side;
}

double Cube::area()
{
	return 6 * side * side;
}

double Cube::volume()
{
	return side * side * side;
}

void Cube::toString()
{
	cout << "Characteristics of this cube";
	cout << "\nSide   = " << getSide();
	cout << "\nArea   = " << area();
	cout << "\nVolume = " << volume() << "\n\n";
}

//Main File: Exo.cpp

//#include "cube.h"

void main()
{
	Cube cube;
	cube.setSide(-12.55);
	cube.toString();
}

Objective #2: Create a simple hello world program in C

The language C does not allow classes. It is not an object-oriented programming language. It was created in the early 1970's by Dennis Ritchie and is still used today. It executes very quickly and interfaces directly with hardware. It is great for systems level programming. It is not great for large business applications.
Click the menu command Start/All Programs/Microsoft Visual Studio .NET 2003/Microsoft Visual Studio .NET 2003 to open MS Visual Studio.
Click the menu command File/New Project to create a project. Click Visual C++ Projects under "Project Types" in the left panel. Select the "Empty Project (.NET)" icon under "Templates" in the right panel. Type the name "CHelloWorld" and verify that the Location is your student network folder. Then click the OK button.
Click the menu command Project/Add New Item. Click the "C++ File (.cpp)" icon under "Templates" in the right panel. Type the name "CHelloWorld.c" for Name and click the Open button.
Type the following code:

#include <stdio.h>

void main()
{
printf("hello world\n");
}
Click the menu command Build/Compile to compile the program and check for errors. Errors are listed in the Output window in the lower pane.
Click the menu command Debug/Start Without Debugging to execute the program.
Here is a more complicated example that allows for user input and that includes a static function.

#include <stdio.h>

double add(int x, double y)
{
   return x + y;
}

void main()
{
   int a = 0;
   double b = 0;
   double answer = 0;
   char name[20];
   printf("Enter your name, an integer, and a decimal value: ");
   scanf("%s", &name);
   scanf("%d", &a);
   scanf("%lf", &b);
   answer = add(a, b);
   printf("%s, the answer is %lf\n", name, answer);
}

Objective #3: Create a simple hello world program in C#

Microsoft first developed the object-oriented C# language that has a syntax based on C++ but that has also been influenced by Java. It is meant to be easy to use like another Microsoft language, Visual Basic.
Click the menu command Start/All Programs/Microsoft Visual Studio .NET 2003/Microsoft Visual Studio .NET 2003 to open MS Visual Studio.
Click the menu command File/New Project to create a project. Click Visual C# Projects under "Project Types" in the left panel. Select the "Empty Project (.NET)" icon under "Templates" in the right panel. Type the name "CsharpHelloWorld" (I don't like using the symbol # in a filename) and verify that the Location is your student network folder. Then click the OK button.
Click the menu command Project/Add New Item. Click the "Code File" icon under "Templates" in the right panel. Type the name "CsharpHelloWorld.cs" for Name and click the Open button.
Type the following code:

public class Hello
{
   public static void Main()
   {
      System.Console.WriteLine("hello world");
   }
}
Click the menu command Debug/Start Without Debugging to execute the program.

Here is a more complicated example that allows for user input and that includes a static method.

using System;

public class Hello
{
	public static int Add(int x, double y)
	{
		return x + (int) y;
	}

	public static void Main()
	{
		int a = 0;
		double b = 0;
		string name = "";
		double answer = 0;

		System.Console.Write("Enter your name: ");
		name = Console.ReadLine();

		System.Console.Write("Enter an integer: ");
		a = int.Parse(Console.ReadLine());

		System.Console.Write("Enter a decimal value: ");
		b = double.Parse(Console.ReadLine());

		answer = Add(a, b);
		System.Console.WriteLine("{0}, the answer is {1}", name, answer); 
	}
}

Here is a more complicated example that uses a class.

	
public class Calculation
{
	private int result;

	//constructor
	public Calculation()
	{
		result = 0;
	}
	
	public Calculation(int x)
	{
		result = x;
	}
	
	//destructor
	~Calculation()
	{
		result = 0;
	}
	
	//methods
	public void displayResult()
	{
		System.Console.WriteLine("Result = {0}", result);
	}
	
	public void add(int x)
	{
		result = result + x;
	}
	
	public void subtract(int x)
	{
		result = result - x;
	}
}

public class Demo
{
	public static void Main()
	{
		Calculation myCalculation = new Calculation(90);
		myCalculation.displayResult();
		myCalculation.add(45);
		myCalculation.displayResult();
		myCalculation.subtract(35);
		myCalculation.displayResult();
		myCalculation.subtract(110);
		myCalculation.displayResult();
	}
}