Iterative Statements

In Go, Iterative statements allows you you repeat a set of instructions mutiple times, which is primarily achieved using for loop. Unlike many other programming languages, Golang only has one looping construct: for. It can be used in different forms to handle variety of iteration needs.

1. Basic for Loop

The most common form of the for loop is similar to that in other languages, where you specify initialization, a condition, and incrementation.

// Example

package main

import "fmt"

func main() {
    for i := 0; i < 5; i++ {
        fmt.Println(i)
    }
}

• i := 0 initializes the loop variable.
• i < 5 is the condition that controls how long the loop will continue.
• i++ increments i by 1 on each iteration.
• This loop will print numbers from 0 to 4.

2. for as a while Loop

In Golang, for can be used without any statements in the initializer and post sections, making it behave like a while loop.

// Example

package main

import "fmt"

func main() {
    i := 0
    for i < 5 {
        fmt.Println(i)
        i++
    }
}

• This loop will run as long as i < 5 is true.
• Here, i is incremented manually inside the loop.

3. Infinite Loop

If you omit all three components of the for loop, it creates an infinite loop. You can exit it using a break statement when a specific condition is met.

// Example

package main

import "fmt"

func main() {
    i := 0
    for {
        if i >= 5 {
            break
        }
        fmt.Println(i)
        i++
    }
}

4. for Range Loop (for Iterating Over Collections)

The for ... range loop is used to iterate over collections like arrays, slices, maps, or strings.

// Example

package main

import "fmt"

func main() {
    numbers := []int{1, 2, 3, 4, 5}

    for index, value := range numbers {
        fmt.Printf("Index: %d, Value: %d\n", index, value)
    }
}

5. Using continue and break

continue skips the current iteration and moves to the next one, while break exits the loop.

// Example

package main

import "fmt"

func main() {
    for i := 0; i < 10; i++ {
        if i%2 == 0 {
            continue // Skip even numbers
        }
        if i > 7 {
            break // Stop the loop if i is greater than 7
        }
        fmt.Println(i) // This will print only odd numbers up to 7
    }
}

Summary

Type of Loop	Syntax	Description
Basic for Loop	for i := 0; i < 5; i++ { ... }	Executes a block of code a specific number of times. Used with initializer, condition, and post-statement.
for as while Loop	for condition { ... }	Repeats as long as the condition is true. Useful when you don’t need an initializer or post-statement.
Infinite Loop	for { ... }	Runs indefinitely until a break is used to exit the loop.
for ... range Loop	for index, value := range collection { ... }	Iterates over collections (e.g., arrays, slices, maps). Returns index and value for each element in the collection.
continue and break Control	continue, break inside for loop	continue skips the current iteration; break exits the loop entirely.