Functions / Methods

A function is a block of code that will run whenever we call it, think of our Main function.

Example

C++

int main()
{
    return 0;
}

We usually use functions / methods to make our code easier to read, organized, reusable, etc.

In object-oriented programming, a method is simply a function that belongs to a class or object.

In C#, every function is technically a method, because all code must reside in a class.

Anatomy of a Function / Method

Component	Description	Example
Return Type	Data type returned after execution	int, void
Name	Identifier used to call the function	Add, PrintLine
Parameters	Input values used inside the function	(int a, int b)
Body	Block of statements executed when called	{ return a + b; }

Example

C++C#

int Add(int a, int b) 
{
    return a + b; // Returns the sum of a and b as an integer type
}

void PrintLine(std::string sentence) 
{
    std::cout << sentence << std::endl; // Prints the provided sentence to the console
}

void PrintLine() 
{
    std::cout << "I got passed 0 arguments." << std::endl; // No parameters
}

int Add(int a, int b) 
{
    return a + b; // Returns the sum of a and b as an integer type
}

void PrintLine(string sentence)
{
    Console.WriteLine(sentence); // Prints the provided sentence to the console
}

void PrintLine() 
{
    Console.WriteLine("I got passed 0 arguments."); // No parameters
}

Note

You might notice we have two PrintLine() functions.

This is called function overloading—multiple functions can share the same name if their parameter lists or functions signature differs.

Calling these functions would look something like this:

Example

C++C#

// When we call functions we pass arguments for the asked parameters.
int a = Add(5, 5);
PrintLine("int a is equal to: " + std::to_string(a));
PrintLine();

// When we call functions we pass arguments for the asked parameters.
int a = Add(5, 5);
PrintLine("int a is equal to: " + a);
PrintLine();