Answer Posted / abdur rab

A pointer variable which holdes the address of a function
is a function pointer.

eg:
declaration of function pointer

void (*function_name)( int, int ) = NULL;

defining a function

void sum ( int x, int y )
{
printf ( "\nThe sum :%d", x + y );
}

void difference ( int x, int y )
{
printf ( "\nThe difference :%d", x - y );
}

using the function pointer in the place of function.
Remember to use the same prototype as declared.

int main ( int argc, char* argv [] )
{
function_name = sum; //short way of doing
function_name = ∑ // best practice

function_name ( 10, 20 ); //short way of doing
(*function_name) ( 10, 20 ); //best practice

function_name = &difference; //best practice
(*function_name) ( 10, 20 ); //best practice

return ( 0 );
}

output
======

The sum :30
The difference :-10

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