**Introduction**

This is tutorial of c++ of functions. The first program find the sum of two numbers using functions. The second one also does so. There is a little difference in the method of these programs but output is same. The program can be extended. Look at the extending it section. Go enjoy the program. Lets begin……………

**Program to find sum of two numbers using function (method 1).**

```
#include<iostream.h>
#include<conio.h>
//global variables int
int a,b,c;
//function prototype
void sum(void);
//main function
void main()
{
//clear the screen.
clrscr();
//Input the two numbers save them in 'a' and 'b'
cout<<"Enter the no."<<endl;
cin>>a>>b;
//calculate sum using sum function.
sum();
//get character
getch();
}
//function
void sum(void)
{
c=a+b;
cout<<"Sum of "<<a<<" & "<<b<<" is "<<c;
}
```

**Output**

Enter the no.

1

2

Sum of 1 & 2 is 3

**Program to find sum of two numbers using function (method 2).**

#include<iostream.h>

#include<conio.h>

//function prototype

int sum(int,int);

//main function

void main()

{

//clear the screen.

clrscr();

//declare variables as int.

int a,b,c;

//Input the two numbers save them in ‘a’ and ‘b’

cout<<“Enter the no.”<<endl;

cin>>a>>b;

//calculate sum using sum function.

c=sum(a,b);

//print sum

cout<<“Sum of “<<a<<” & “<<b<<” is “<<c;

//get character

getch();

}

//function

int sum(int x,int y)

{

int z;

z=x+y;

return(z);

}

**Output**

Enter the no.

1

2

Sum of 1 & 2 is 3

**How does it work**

- You enter the number.
- The function calculates sum.
- The sum is printed.

**Extending it**

The program can be extended by using more numbers or look here :-

- Subtraction of two numbers using function.
- Multiplication of two numbers using function.
- Division of two numbers using function.

Go extend it…..

**Explanation.**

- Include ‘iostream.h’ and ‘conio.h’ files.
- Declare global variables if required.
- Declare the function prototype.
- Add void main.
- Start program by first clearing the screen.
- Declare the variables as int (name them as you want.)
- Add the cout and cin of numbers.
- Call the function.
- Add the function definition outside the void main().

**At the end**

You learnt creating the C++ program of Sum of two numbers using function. So now enjoy the program.

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