How to Declare a Pointer to a Union in C?

How to Create a Typedef for a Function Pointer in C?

Last Updated : 28 Feb, 2024

In C, a function pointer is a variable that stores the address of a function that can later be called through that function pointer. The typedef is a keyword used to create an alias or alternative name for the existing data types. In this article, we will learn how to create a typedef for a function pointer in C.

Typedef for a Function Pointer in C

To create a typedef for a function pointer, we specify the return type of the function, followed by an asterisk (*) and the name of the typedef in parentheses. We also need to specify the number and types of parameters of the function pointer.

Syntax

typedef return_type (*alias_name)(parameter_types and numbers....);

Here, return_type is the return type of the function alias-name is the alias we want to give to the function pointer type and parameter_types are the types of the parameters the function takes.

C Program to Create a Typedef for a Function Pointer in C

// C Program for how to create a Typedef for a Function
// Pointer
#include <stdio.h>

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

// Function to the subtract two integers
int subtracts(int a, int b) { return a - b; }

// Driver Code
int main()
{
    // Declare function pointers using typedef
    Operation operationAdd = add;
    Operation operationSubtract = subtracts;
    printf("Addition result: %d\n", operationAdd(20, 9));
    printf("Subtraction result: %d\n",
           operationSubtract(20, 9));
    return 0;
}

 
// C Program for how to create a Typedef for a Function
// Pointer
#include <stdio.h>
​
typedef int (*Operation)(int, int);
int add(int a, int b) { return a + b; }
​
// Function to the subtract two integers
int subtracts(int a, int b) { return a - b; }
​
// Driver Code
int main()
{
    // Declare function pointers using typedef
    Operation operationAdd = add;
    Operation operationSubtract = subtracts;
    printf("Addition result: %d\n", operationAdd(20, 9));
    printf("Subtraction result: %d\n",
           operationSubtract(20, 9));
    return 0;
}

Output

Addition result: 29
Subtraction result: 11

How to Declare a Pointer to a Union in C?

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