forExample.go

package main

//imported the package fmt
import "fmt"

//main function gets called when the program runs
func main() {
	//declared a variable with initial value = 0
	sum := 0
	//for loop initialization, with index<5 and incremented by one at a time using index ++
	for index := 0; index < 5; index++ {
		//add the value of index in sum
		sum += index
	}
	//print the value of sum
	fmt.Println("sum =", sum)
}

>>go run forExample.go
>>sum = 10