Function Pointer in C

Function Pointer in C

Function pointer known as Pointer to a function.The code of a function always resides in memory, which means that the function has some address and we can get the address of memory by using the function pointer.

Declaration of Function pointer

The function pointer name is preceded by the indirection operator ( * )

return type (*ptr_name)(type1, type2…);

Example 1

int (*pt) (int);

Here, *pt is a pointer that points to a function that returns an int value and accepts an integer value as an argument.

Example 2

float (*ft) (float);

Here, *ft is a pointer that points to a function that returns an int value and accepts a float value as an argument.

Program

int sum (int num1, int num2)
{
    return num1+num2;
}
int main()
{

    /* The following two lines can also be written in a single
     * statement like this: void (*fun_ptr)(int) = &fun;
     */
    int (*f2p) (int, int);
    f2p = sum;
    //Calling function using function pointer
    int op1 = f2p(10, 13);

    //Calling function in normal way using function name
    int op2 = sum(10, 13);

    printf("Output1: Call using function pointer: %d",op1);
    printf("\nOutput2: Call using function name: %d", op2);

    return 0;
}

Output

Output1: Call using function pointer: 23
Output2: Call using function name: 23

Also, read the Break and continue in C