Functions: Basics

Functions allow you to organize your code into reusable blocks that can be called multiple times. They're essential for avoiding repetition and making your code more maintainable.

Defining a Function

To create a function in Go, you use the func keyword, followed by the function name, parameters in parentheses, and the function body in curly braces:

func greet() {
    fmt.Println("Hello!")
}

This simple function takes no parameters and prints "Hello!" when called.

Calling a Function

Once you've defined a function, you can call it by using its name followed by parentheses:

func greet() {
    fmt.Println("Hello!")
}

func main() {
    greet()  // Calls the function
    greet()  // You can call it multiple times
}
// Output:
// Hello!
// Hello!

Functions with Parameters

Functions become much more powerful when they accept parameters. Parameters allow you to pass data into the function:

func greet(name string) {
    fmt.Println("Hello,", name)
}

func main() {
    greet("Goku")    // Output: Hello, Goku
    greet("Vegeta")  // Output: Hello, Vegeta
}

The parameter name string means the function expects a string value to be passed in when called.

The Problem Functions Solve

Imagine you need to check if multiple characters' power levels are over 9000:

// Without functions - repetitive!
if goku.PowerLevel > 9000 {
    fmt.Println("It's over 9000!")
}

if vegeta.PowerLevel > 9000 {
    fmt.Println("It's over 9000!")
}

if gohan.PowerLevel > 9000 {
    fmt.Println("It's over 9000!")
}

This is tedious and error-prone. With a function:

func checkPowerLevel(powerLevel int) {
    if powerLevel > 9000 {
        fmt.Println("It's over 9000!")
    }
}

func main() {
    checkPowerLevel(goku.PowerLevel)
    checkPowerLevel(vegeta.PowerLevel)
    checkPowerLevel(gohan.PowerLevel)
}

Much cleaner! The logic is written once and reused three times.

Parameter Types

Parameters must have a type specified. This tells Go what kind of data the function expects:

func printNumber(n int) {
    fmt.Println("Number:", n)
}

func printName(name string) {
    fmt.Println("Name:", name)
}

func printActive(isActive bool) {
    fmt.Println("Active:", isActive)
}

Assignment

For this challenge, create a function called transformationBoost that accepts a parameter basePower (an int).

The function should:

• Check if basePower is greater than or equal to 5000
• If yes, print "Transformation unlocked!"
• If no, print "Not strong enough yet"

Then in your main function, call transformationBoost three times with these values: 4500, 5000, and 7000.

The function signature should be:

func transformationBoost(basePower int) {
    // Your code here
}

Expected output:

Not strong enough yet
Transformation unlocked!
Transformation unlocked!