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what is a function pointer and how all to declare ,define
and implement it ???

Answers were Sorted based on User's Feedback



what is a function pointer and how all to declare ,define and implement it ???..

Answer / 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 = &sum; // 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

Is This Answer Correct ?    9 Yes 1 No

what is a function pointer and how all to declare ,define and implement it ???..

Answer / satish

Function pointer:
a function can be called not only by
its name,but also by other name which is called function
pointer.

void fact(int);
void main()
{
void(*p)(int);
printf("Enter n\n");
scanf("%d",&n);
p=fact;
fact(n);/*normal calling a function*/
(*p)(n); /*fn calling using function pointer*/

}
void (*p)(int n)
{
int ans=1;
while(n>0)
{
ans*=n--;
}

printf(" %d != %d",n,ans);

Is This Answer Correct ?    3 Yes 4 No

what is a function pointer and how all to declare ,define and implement it ???..

Answer / swagatika

function pointer is function returning a pointer
Example-

int *sum(int a, int b)
{
int x;
x= a+b;
return &x;
}

but the pointer to a function means a function interm of
pointer pointing to the another function.

int (*sum)(sum1);//pointer to a function

Is This Answer Correct ?    0 Yes 1 No

what is a function pointer and how all to declare ,define and implement it ???..

Answer / mathiyazhagan

A function can itself stored in a memory address.By calling
the address ,instead of function name,we can invoke
function.
Eg.:
#include <stdio.h>
void sum(int,int);
{
void (*fp)(); //() denotes pointer to a function
fp=sum(); // no need & .reason : same of array
fp(10,20); //invoking function
}
void sum(int x,int y)
{
printf("sum of x%d and %d is =%d",x,y,x+y);
}

Is This Answer Correct ?    1 Yes 5 No

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