Magic Boxes, Functions

In C++, you can bundle common code and give it a name. This is called a function.

Create a function

When you define a function, you must clearly specify the input and output types.

// 1. Greeting function (returns nothing -> void)
void sayHello() {
    std::cout << "Hello!" << std::endl;
}

// 2. Add function (returns a number)
int add(int a, int b) {
    return a + b;
}

int main() {
    sayHello(); // use it
    
    int result = add(10, 20);
    std::cout << "Result: " << result << std::endl;
    return 0;
}

Translation:

Define a magic box called add:
    (output is an int)
    (inputs are numbers a and b)
    {
        return a + b
    }

Why so strict?

In C++, if you declare “this function takes ints and returns an int,” the language enforces it. That reduces the chance of crashes or weird values.

This precision is where C++ strength begins.