Call By Value

In the technique of " Call By Value " the compiler passes the value of the argument. When a single value ( or a single variable ) is passed to function as an actual argument is copied into the formal argument ( i.e. onto the function ).
Now, the value of the corresponding formal argument can be altered within the function, but the value of actual argument within the calling portion will remain same . Thus the changes done in the function will not be reflected in calling portion.
This procedure of passing value of an argument to a function is known as call by value or pass by value. consider example of swapping of two numbers:


#include<stdio.h>
	void swap(int ,int);
	void main(){
	  int a=5,b=10;
	  swap(a,b);
	  printf("value main function after swapping in swap function \n a=%d and b=%d",a,b);
	}
	
	void swap(int a,int b){
	  int temp=a;
	  a=b;
	  b=temp;
	  printf("value inside swap function after swapping \n a=%d and b=%d\n",a,b);
	}

Output:


value inside swap function after swapping 
a=10 and b=5
value in main function after swapping in swap function
a=5 and b=10

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