fizzbuzz_3.go

package main                                                                                                                                                                                  
                                                                                                                                                                                              
import (                                                                                                                                                                                      
        "fmt"                                                                                                                                                                                 
        "sync"                                                                                                                                                                                
)                                                                                                                                                                                             
                                                                                                                                                                                              
func main() {                                                                                                                                                                                 
        routineCount := 100                                                                                                                                                                   
                                                                                                                                                                                              
        // bootstrapping the waitgroup                                                                                                                                                        
        var wg sync.WaitGroup                                                                                                                                                                 
        // increment the routine count                                                                                                                                                        
        wg.Add(routineCount)                                                                                                                                                                  
        for i := 1; i <= routineCount; i++ {                                                                                                                                                  
                // it is possible to do it here as long as wg is increment before goroutine                                                                                                   
                // wg.Add(1)                                                                                                                                                                  
                                                                                                                                                                                              
                // gotcha of closure with goroutine                                                                                                                                           
                go func(i int) {                                                                                                                                                              
                        fizzbuzz(i)                                                                                                                                                           
                        wg.Done()                                                                                                                                                             
                }(i)                                                                                                                                                                          
        }                                                                                                                                                                                     
                                                                                                                                                                                              
        // Block until all executed                                                                                                                                                           
        wg.Wait()                                                                                                                                                                             
}                                                                                                                                                                                             
                                                                                                                                                                                              
func fizzbuzz(i int) {                                                                                                                                                                        
        // 0 padding for prettier output                                                                                                                                                      
        msg := fmt.Sprintf("%03d - ", i)                                                                                                                                                      
        if i%3 == 0 {                                                                                                                                                                         
                msg += "fizz"                                                                                                                                                                 
        }                                                                                                                                                                                     
                                                                                                                                                                                              
        if i%5 == 0 {                                                                                                                                                                         
                msg += "buzz"                                                                                                                                                                 
        }                                                                                                                                                                                     
                                                                                                                                                                                              
        fmt.Println(msg)                                                                                                                                                                      
}