Loops: for keyword

Loops allow you to execute code repeatedly without writing the same statements over and over. In Go, there's only one looping construct: the for loop. However, it's incredibly flexible and can be used in many different ways.

The Infinite Loop

The simplest form of a for loop in Go is an infinite loop - a loop that runs forever (or until you tell it to stop).

for {
    fmt.Println("This will run forever!")
}

This might seem scary, but it's actually quite useful when combined with ways to exit the loop.

The break Keyword

The break keyword allows you to exit a loop early, giving you full control over when to stop looping.

count := 0
for {
    fmt.Println("Looping...")
    count++
    
    if count == 3 {
        break  // Exit the loop when count reaches 3
    }
}
fmt.Println("Loop finished!")

This will print "Looping..." exactly 3 times, then exit the loop and print "Loop finished!".

How it Works

The loop runs continuously until it encounters a break statement. This pattern gives you complete control over when to exit based on any condition you want.

userInput := ""
for {
    fmt.Println("Enter 'quit' to exit:")
    // (imagine getting user input here)
    
    if userInput == "quit" {
        break
    }
    
    fmt.Println("You entered:", userInput)
}

Using a Counter

A common pattern is to use a counter variable to track how many times the loop has run.

iterations := 0
for {
    fmt.Println("Iteration:", iterations)
    iterations++
    
    if iterations == 5 {
        break
    }
}
// Prints 5 times (iterations 0 through 4)

Assignment

For this challenge, create a function called countUp that accepts a parameter n (an integer).

The function should:

• Use an infinite for loop
• Keep track of a counter starting at 0
• Print the current counter value on each iteration
• Use an if statement to check when the counter equals n
• Use break to exit the loop when the counter reaches n

The function signature is:

func countUp(n int) {
    // Your code here
}

For example, calling countUp(3) should print:

0
1
2