0 Pointer & functions -Pointers

When an array is passed to a function as an argument , only the address of the first element of the array is passed , but not the actual values of the array elements.

If x is an array, when we call sort(x), the address of x[0] is passed to the function sort().

The function uses this address for manipulating the array elements.

The address of a variable can be passed as an argument to a function in the normal fashion.

When address is passed to a function , the parameters receiving the address should be pointers.

The process of calling a function using pointer to pass the address of variable is known as call by reference.

The function which is called by reference can change the value of the variable used in the call.

Example:

main()

{

int x;

x=20;

change(&x);

printf("%d\n",x);

}

change( int *p)

{

*p=*p+10;

}

Explanation: When the function change() is called, the address of the variable x, not its value, is passed into the function change().

Inside change(), the value at which p points is incremented by 10 , and the changed value is then displayed in the main function.

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