Functions in C++

Modularity refers to the degree to which a system's components can be separated and recombined, often for increased flexibility and variety of use. It's a concept that can be applied across various disciplines, including engineering, computer science, and biology.

A simple example of a function in C++ that returns a value:

#include <iostream>

using namespace std;

int multiply(int x, int y) {

    return x * y;

}

int main() {

    int result = multiply(4, 5);

    cout << "The result is: " << result << endl;  // Output: The result is: 20

    return 0;

}

A function is a reusable block of code that performs a specific task. It can take inputs (parameters), do something, and optionally return a value.

Parameter: a variable in the function definition that receives a value

Argument: the actual value passed to the function when it is called

Use const in parameters when you don’t want them modified

A global function is defined outside of any class and can be accessed from anywhere in the file (or other files if declared properly).

Functions defined inside a class are called member functions. They operate on the data members of the class and can be either public or private.

In C++, a function signature is the part of a function declaration that includes the function name and the parameter types (but not the return type or parameter names).

In C++, the return type of a function specifies the type of value that the function will send back to the caller when it finishes executing.

What Is a Return Type?

It’s the data type declared before the function name that tells the compiler what kind of result to expect.

A function declaration tells the compiler, “This function exists, and here’s how it should be called.”

It does not contain the body of the function—just the signature and return type.

A function definition provides the actual implementation of a function. It includes:

- The return type

- The function name

- The parameter list

- The body (code that runs when the function is called)

A function prototype is a declaration that tells the compiler, “This function exists, and here’s how it should be called.”

It’s usually placed before main() or in a header file so the compiler knows about the function before it’s used.

Microsoft Copilot