Default Parameter Values

Sometimes it's useful to set a default value for a parameter. For example, when a parameter value is often repeated.

Default parameter values allow us to call a function without having to specify all parameter values. If a value for a parameter with a default value is not provided, its default value is used. We set the default value of a parameter during function definition using the = operator. For example:

void greet(std::string name = "world") {
    std::cout << "Hello, " << name << std::endl;
}

This function has one parameter name of type std::string with a default value of "world". When we call the function without a parameter value:

greet(); // Prints: Hello, world

The function uses the default value and prints Hello, world.

When we call the function with a parameter value:

greet("Charlie"); // Prints: Hello, Charlie

The function uses the provided value and prints Hello, Charlie.