{"id":15662,"date":"2023-04-19T11:48:36","date_gmt":"2023-04-19T11:48:36","guid":{"rendered":"https:\/\/www.prepbytes.com\/blog\/?p=15662"},"modified":"2024-05-15T12:45:50","modified_gmt":"2024-05-15T12:45:50","slug":"function-pointer-in-cpp","status":"publish","type":"post","link":"https:\/\/prepbytes.com\/blog\/function-pointer-in-cpp\/","title":{"rendered":"Function Pointer in C++"},"content":{"rendered":"

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In C++, functions are treated as first-class citizens, which means they can be passed as arguments to other functions, returned from functions, and stored in data structures. Function pointers allow us to store the address of a function and later call that function through the pointer. This feature is particularly useful in scenarios where we need to select and call a function dynamically at runtime.<\/p>\n

What is Function Pointer in C++?<\/h2>\n

A function pointer in C++ is a variable that stores the memory address of a function. In C++, a function is treated like any other variable, and it can be passed as an argument to another function or returned as a value from a function. When a function is passed as an argument to another function, it is referred to as a C++ function pointer.<\/p>\n

How to Declare a Function Pointer in C++?<\/h3>\n

To declare a function pointer in C++, we use the following syntax:<\/p>\n

return_type (*pointer_name)(argument_type1, argument_type2, ...);<\/code><\/pre>\n
Example of How to Declare Function Pointer in C++<\/strong>
\nIf we want to declare a C++ function pointer that points to a function that takes two integer arguments and returns an integer, we would use the following syntax:<\/p>\n
int (*func_ptr)(int, int);<\/code><\/pre>\n
Here, func_ptr is a pointer to a function that takes two integer arguments and returns an integer. We can use this pointer to call the function at runtime.<\/p>\n
How to Assign a C++ Function Pointer to a Function?<\/h3>\n
Once we have declared a function pointer, we can assign it to a function using the following syntax.<\/p>\n
pointer_name = function_name;<\/code><\/pre>\n
Example of Assigning C++ Function Pointer to a Function:<\/strong>
\nIf we have a function called addNumbers that takes two integer arguments and returns their sum, we can assign its address to a function pointer using the following line of code.<\/p>\n
int (*addNumbers_ptr)(int, int) = &addNumbers;<\/code><\/pre>\n
Here, we are assigning the address of the addNumbers function to the addNumbers_ptr pointer. Now, we can use this pointer to call the addNumbers to function at runtime.<\/p>\n
How to Call a Function Using a Function Pointer in C++?<\/h3>\n
To call a function using a function pointer in C++, we use the following syntax:<\/p>\n
(*pointer_name)(argument1, argument2, ...);<\/code><\/pre>\n
Example:<\/strong>
\nIf we want to call the addNumbers function using the addNumbers_ptr pointer, we will use the following line.<\/p>\n
int result = (*addNumbers_ptr)(2, 3);<\/code><\/pre>\n
Here, we are calling the addNumbers function using the addNumbers_ptr pointer and passing two integer arguments. The result variable will store the sum of these two integers.<\/p>\n
Examples of Function Pointer in C++<\/h3>\n
Now let us understand the Function Pointer in C++ with the help of the following examples.<\/p>\n
Example 1 of C++ Function Pointer<\/strong>
\nUsing a function pointer in C++ to pass a function as an argument to another function.<\/p>\n
Code:<\/strong><\/p>\n\t\t\t\t\t\t