package main import ( "bufio" "fmt" "io" "os" ) func countChars(file string, ch chan int) { f, err := os.Open(file) if err != nil { ch <- 0 return } defer f.Close() r := bufio.NewReader(f) count := 0 for { _, size, err := r.ReadRune() if err == io.EOF { break } else if err != nil { ch <- 0 return } count += size } ch <- count } func countWords(file string, ch chan int) { f, err := os.Open(file) if err != nil { ch <- 0 return } defer f.Close() r := bufio.NewReader(f) count := 0 scanner := bufio.NewScanner(r) scanner.Split(bufio.ScanWords) for scanner.Scan() { count++ } if err := scanner.Err(); err != nil { ch <- 0 return } ch <- count } func countLines(file string, ch chan int) { f, err := os.Open(file) if err != nil { ch <- 0 return } defer f.Close() r := bufio.NewReader(f) count := 0 scanner := bufio.NewScanner(r) scanner.Split(bufio.ScanLines) for scanner.Scan() { count++ } if err := scanner.Err(); err != nil { ch <- 0 return } ch <- count } func countBytes(file string, ch chan int64) { info, err := os.Stat(file) if err != nil { ch <- 0 return } ch <- info.Size() } func main() { args := os.Args if len(args) == 1 { fmt.Printf("usage: wc [ ...]\n") return } totalChars := 0 totalWords := 0 totalLines := 0 totalBytes := int64(0) charCh := make(chan int) wordCh := make(chan int) lineCh := make(chan int) byteCh := make(chan int64) for _, file := range args[1:] { go countChars(file, charCh) go countWords(file, wordCh) go countLines(file, lineCh) go countBytes(file, byteCh) totalChars += <-charCh totalWords += <-wordCh totalLines += <-lineCh totalBytes += <-byteCh fmt.Printf("%8d %8d %8d %8d %8s (chars, words, lines, bytes, file) \n", totalChars, totalWords, totalLines, totalBytes, file) } }

Solution 1: Go Concurrency

Solution

Code explanation