Creating a Class and Call it from Main Program

This article tells you how to create your own class with some function in it and how to call these functions from main.

1. Creating your class : This is how my class mcCalculator look like. Its has five functions besides constructor and destructor called Add, Subtract, Devide ( spell mistake ) , Multiply, and DisplayOutVal. As you can see from their names, these functions adds, subtracts, multiplies, divides correspondingly and stores result in a private variable iOutVal which is called by DisplayOutVal to display the result.

public class mcCalculator
{
private int iOutVal;
//Default constructor
public mcCalculator()
{
iOutVal = 0;
}
public mcCalculator(int iVal1 )
{
iOutVal = iVal1 ;
}
//destructor
~mcCalculator()
{
iOutVal = 0;
}
//methods
public void displayiOutVal()
{
Console.WriteLine("iOutVal = {0}", iOutVal);
}
// this function adds two values and saves in iOutVal
public void add(int iVal1, int iVal2 )
{
iOutVal = iVal1 + iVal2 ;
}
// this function subtracts one from other and saves in iOutVal
public void subtract(int iVal1, int iVal2 )
{
iOutVal = iVal1 - iVal2 ;
}
// this function multiplyies two values and saves in iOutVal
public void Multiply(int iVal1, int iVal2 )
{
iOutVal = iVal1 * iVal2 ;
}
// this function devides one value from other and saves in iOutVal
public void Devide(int iVal1, int iVal2 )
{
iOutVal = iVal1 / iVal2 ;
}
}

2. Calling your class from Main : Now call mcCalculator from main. First create instance of mcCalculator and then call its member functions.

// Main Program
class mcStart
{
public static void Main()
{
mcCalculator mcCal = new mcCalculator(50);
mcCal.add(12, 23 );
mcCal.displayiOutVal();
mcCal.subtract( 24, 4 );
mcCal.displayiOutVal();
mcCal.Multiply( 12, 3 );
mcCal.displayiOutVal();
mcCal.Devide( 8, 2 );
mcCal.displayiOutVal();
}
}

3. Don't forget to call using System; as first line of your file.

Quick Method: Download attached file second.cs and run from command line csc second.cs.