🔴 Advanced · Lesson 35

Function Pointers

What is Function Pointer?

A function pointer stores the address of a function. It can be used to call a function dynamically, pass functions as arguments and implement callbacks.

Syntax

return_type (*pointer_name)(parameter_types);

int (*fp)(int, int);   // pointer to a function taking two int and returning int

Calling Function Pointer

C Language

#include <stdio.h>

int add(int a, int b) {
    return a + b;
}

int main() {
    int (*fp)(int, int);
    fp = add;

    printf("Sum = %d", fp(10, 20));
    return 0;
}

Sum = 30

Callback Example

C Language

#include <stdio.h>

int add(int a, int b) { return a + b; }
int sub(int a, int b) { return a - b; }
int mul(int a, int b) { return a * b; }

void calculate(int x, int y, int (*operation)(int, int)) {
    printf("Result = %d\n", operation(x, y));
}

int main() {
    calculate(10, 5, add);
    calculate(10, 5, sub);
    calculate(10, 5, mul);
    return 0;
}

Result = 15 Result = 5 Result = 50

Summary

Function pointer stores function address
Syntax uses parentheses: int (*fp)(int,int)
Function name itself represents its address
Useful for callback, menu, sorting and event handling
Read function pointer declarations carefully from inside out

Function Pointer क्या है?

Function pointer किसी function का address store करता है। इसके द्वारा function को dynamically call कर सकते हैं और callback बना सकते हैं।

Syntax

C Language

return_type (*pointer_name)(parameter_types);
int (*fp)(int, int);

Call करना

C Language

int add(int a, int b) { return a + b; }

int (*fp)(int, int) = add;
printf("%d", fp(10, 20));

Callback Example

C Language

void calculate(int x, int y, int (*op)(int, int)) {
    printf("%d", op(x, y));
}

सारांश

Function pointer function का address store करता है
Syntax में parentheses important हैं
Function name address represent कर सकता है
Callback और menu based programs में useful है
Declaration को carefully पढ़ें

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