Make goroutines wait for each other

Use the WaitGroup type from the golang.org/pkg/sync package as a semaphore to tell goroutines to wait or release handles.

import (
    "fmt"
    "sync"
)

func PrintSum(slice []int, wg *sync.WaitGroup) {
    defer wg.Done()
    var sum int
    for _, num := range slice {
        sum += num
    }
    fmt.Println(sum)
}

func main() {
    slice := 
    wg := &sync.WaitGroup{}

    wg.Add(3)
    go PrintSum([]int{1, 2, 3, 4, 5}, wg)
    go PrintSum([]int{2, 4, 6, 8, 10}, wg)
    go PrintSum([]int{11, 22, 33, 44}, wg)
    wg.Wait()
}

References

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