update book code

eBook/examples/chapter_7/slices_forrange.go

@@ -1,15 +1,22 @@
-package main
-import "fmt"
-
-func main() {
-    slice1 := make([]int, 4)
-
-    slice1[0] = 1
-    slice1[0] = 2
-    slice1[0] = 3
-    slice1[0] = 4
-
-    for ix, value := range slice1 {
-        fmt.Printf("Slice at %d is: %d\n", ix, value)
-    }
-}
+package main
+
+import "fmt"
+
+func main() {
+	var slice1 []int = make([]int, 4)
+
+	slice1[0] = 1
+	slice1[1] = 2
+	slice1[2] = 3
+	slice1[3] = 4
+
+	for ix, value := range slice1 {
+		fmt.Printf("Slice at %d is: %d\n", ix, value)
+	}
+}
+/*
+Slice at 0 is: 1
+Slice at 1 is: 2
+Slice at 2 is: 3
+Slice at 3 is: 4
+*/