Range Over Channels

Introduction

This lab aims to test your ability to iterate over values received from a channel using the for and range syntax in Golang.

Range Over Channels

You are required to write a function that takes in a channel of integers and returns the sum of all the integers received from the channel.

• The function should be named sumInts.
• The function should take in a single parameter of type chan int.
• The function should return a single integer value.
• You are not allowed to use any loops or recursion inside the function body.
• You are not allowed to use any external packages.

$ go run range-over-channels.go
one
two

## This example also showed that it's possible to close
## a non-empty channel but still have the remaining
## values be received.

There is the full code below:

// In a [previous](range) example we saw how `for` and
// `range` provide iteration over basic data structures.
// We can also use this syntax to iterate over
// values received from a channel.

package main

import "fmt"

func main() {

    // We'll iterate over 2 values in the `queue` channel.
    queue := make(chan string, 2)
    queue <- "one"
    queue <- "two"
    close(queue)

    // This `range` iterates over each element as it's
    // received from `queue`. Because we `close`d the
    // channel above, the iteration terminates after
    // receiving the 2 elements.
    for elem := range queue {
        fmt.Println(elem)
    }
}

Summary

In this lab, you were tasked with writing a function that sums up all the integers received from a channel using the for and range syntax in Golang. By completing this lab, you should have a better understanding of how to iterate over values received from a channel and how to use goroutines to receive values from a channel.