Function Pointer in C++

Pointers are symbolic representations of addresses. They enable programs to simulate call-by-reference as well as to create and manipulate dynamic data structures. Iterating over elements in arrays or other data structures is one of the main use of pointers. The address of the variable you’re working with is assigned to the pointer variable that points to the same data type (such as an int or string). Syntax: datatype *var_name;
Address of Function:

We all know that every function’s code resides in memory, so every function has an address like all other variables in the program. The name of a function can be used to find the address of the function. We can get the address of a function by just writing the function’s name without parentheses in the function.
Referencing and Dereferencing of the Function Pointer in C++

Similar to the pointer used with variables we perform referencing and dereferencing with a function pointer. Referencing: When pointer is allocated the address of the function to be associated with it then this process is referred to as referencing. Dereferencing: When we use the (*)operator to get the value stored in the pointer.
Function pointer used to call the function

In this, we see how we point a pointer to a function and call it using that pointer. It is an efficient way to use Example: // C++ program to implementation // Function Pointer #include <iostream> using namespace std; int multiply(int a, int b) { return a * b; } int main() { int (*func)(int, int); // func is pointing to the multiplyTwoValues function func = multiply; int prod = func(15, 2); cout << "The value of the product is: " << prod << endl; return 0; }
Passing a function pointer as a parameter

When declaring a function pointer to store the memory address of the function but, when we want to pass the return value to the next function. We have two methods to perform this task. First, either pass the value we got or second pass the function pointer that already exists.
Example:Passing a function pointer as a parameter

// C++ Program for demonstrating // function pointer as pointer #include <iostream> using namespace std; const int a = 15; const int b = 2; // Function for Multiplication int multiply() { return a * b; } // Function containing function pointer // as parameter void print(int (*funcptr)()) { cout << "The value of the product is: " << funcptr() << endl; } // Driver Function int main() { print(multiply); return 0; }
How to initialize function pointer in C++?

You need to initialize a pointer by assigning it a valid address. This is normally done via the address-of operator ( & ). The address-of operator ( & ) operates on a variable, and returns the address of the variable. For example, if number is an int variable, &number returns the address of the variable number .
How do you declare a pointer to a function?

So, you would write something like int (*foo)(int) . This makes it clear that foo is a pointer to a function returning an int . int (*foo)(int); By placing the * operator with foo and using parentheses, you've successfully declared a pointer to a function foo that returns an int
What is a function pointer in C++ as a return type?

Function pointers can also appear as the return value of a function. To declare a function with the corresponding function pointer type as the return type, the name of the function must be written in parentheses ( )with the pointer character , along with its argument list *.
How do you call a function pointer in C++?

This is called a function pointer, and it allows you to pass a function as an argument to another function, or to store a function address in a variable. The syntax for defining a function pointer in C++ is: return_type (*function_name)(parameter_list);

Requirement

Pointers are symbolic representations of addresses. They enable programs to simulate call-by-reference as well as to create and manipulate dynamic data structures. Iterating over elements in arrays or other data structures is one of the main use of pointers.

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Pointers are symbolic representations of addresses. They enable programs to simulate call-by-reference as well as to create and manipulate dynamic data structures. Iterating over elements in arrays or other data structures is one of the main use of pointers.

Pointer to function