Control Flow, Functions, Packages, and Code Organization

if, for, and switch

if score >= 80 {
    fmt.Println("Excellent")
} else {
    fmt.Println("Keep learning")
}

for i := 0; i < 3; i++ {
    fmt.Println(i)
}

Go uses for for all looping patterns and offers a clean switch syntax for branch-heavy logic.

Functions

func calculateTotal(price float64, tax float64) float64 {
    return price + (price * tax)
}

Functions define reusable logic and explicit input-output contracts. Go makes return types highly visible, which improves readability.

Multiple Return Values

func divide(a, b float64) (float64, error) {
    if b == 0 {
        return 0, errors.New("division by zero")
    }
    return a / b, nil
}

Go commonly returns a value and an error together. This pattern is central to Go code style and influences how error handling works throughout the language.

Packages and Files

Go code is organized into packages rather than one giant global scope. Good package structure makes larger systems easier to navigate, test, and maintain.

Practical Example

A small backend service may have separate packages for handlers, business logic, data access, and configuration. Package-level organization helps teams reason about ownership and boundaries cleanly.