Data commit

Task/Bulls-and-cows/Go/bulls-and-cows.go

@@ -0,0 +1,68 @@
+package main
+
+import (
+    "bufio"
+    "bytes"
+    "fmt"
+    "math/rand"
+    "os"
+    "strings"
+    "time"
+)
+
+func main() {
+    fmt.Println(`Cows and Bulls
+Guess four digit number of unique digits in the range 1 to 9.
+A correct digit but not in the correct place is a cow.
+A correct digit in the correct place is a bull.`)
+    // generate pattern
+    pat := make([]byte, 4)
+    rand.Seed(time.Now().Unix())
+    r := rand.Perm(9)
+    for i := range pat {
+        pat[i] = '1' + byte(r[i])
+    }
+
+    // accept and score guesses
+    valid := []byte("123456789")
+guess:
+    for in := bufio.NewReader(os.Stdin); ; {
+        fmt.Print("Guess: ")
+        guess, err := in.ReadString('\n')
+        if err != nil {
+            fmt.Println("\nSo, bye.")
+            return
+        }
+        guess = strings.TrimSpace(guess)
+        if len(guess) != 4 {
+            // malformed:  not four characters
+            fmt.Println("Please guess a four digit number.")
+            continue
+        }
+        var cows, bulls int
+        for ig, cg := range guess {
+            if strings.IndexRune(guess[:ig], cg) >= 0 {
+                // malformed:  repeated digit
+                fmt.Printf("Repeated digit: %c\n", cg)
+                continue guess
+            }
+            switch bytes.IndexByte(pat, byte(cg)) {
+            case -1:
+                if bytes.IndexByte(valid, byte(cg)) == -1 {
+                    // malformed:  not a digit
+                    fmt.Printf("Invalid digit: %c\n", cg)
+                    continue guess
+                }
+            default: // I just think cows should go first
+                cows++
+            case ig:
+                bulls++
+            }
+        }
+        fmt.Printf("Cows: %d, bulls: %d\n", cows, bulls)
+        if bulls == 4 {
+            fmt.Println("You got it.")
+            return
+        }
+    }
+}