2016 Update

Task/Synchronous-concurrency/Go/synchronous-concurrency.go

@@ -1,54 +1,32 @@
 package main
 
 import (
-	"bufio"
-	"fmt"
-	"io"
-	"os"
+    "bufio"
+    "fmt"
+    "log"
+    "os"
 )
 
-// main, one of two goroutines used, will function as the "reading unit"
 func main() {
-	// get file open first
-	f, err := os.Open("input.txt")
-	if err != nil {
-		fmt.Println(err)
-		return
-	}
-	defer f.Close()
-	lr := bufio.NewReader(f)
+    lines := make(chan string)
+    count := make(chan int)
+    go func() {
+        c := 0
+        for l := range lines {
+            fmt.Println(l)
+            c++
+        }
+        count <- c
+    }()
 
-	// that went ok, now create communication channels,
-	// and start second goroutine as the "printing unit"
-	lines := make(chan string)
-	count := make(chan int)
-	go printer(lines, count)
-
-	for {
-		switch line, err := lr.ReadString('\n'); err {
-		case nil:
-			lines <- line
-			continue
-		case io.EOF:
-		default:
-			fmt.Println(err)
-		}
-		break
-	}
-
-	// this represents the request for the printer to send the count
-	close(lines)
-	// wait for the count from the printer, then print it, then exit
-	fmt.Println("Number of lines:", <-count)
-}
-
-func printer(in <-chan string, count chan<- int) {
-	c := 0
-	// loop as long as in channel stays open
-	for s := range in {
-		fmt.Print(s)
-		c++
-	}
-	// make count available on count channel, then return (terminate goroutine)
-	count <- c
+    f, err := os.Open("input.txt")
+    if err != nil {
+        log.Fatal(err)
+    }
+    for s := bufio.NewScanner(f); s.Scan(); {
+        lines <- s.Text()
+    }
+    f.Close()
+    close(lines)
+    fmt.Println("Number of lines:", <-count)
 }