more examples

gobyexample/closures.go

@@ -0,0 +1,22 @@
+package main
+
+import "fmt"
+
+func intSeq() func() int {
+	i := 0
+	return func() int {
+		i++
+		return i
+	}
+}
+
+func main() {
+	nextInt := intSeq()
+
+	fmt.Println(nextInt())
+	fmt.Println(nextInt())
+	fmt.Println(nextInt())
+
+	newInts := intSeq()
+	fmt.Println(newInts())
+}

gobyexample/functions.go

@@ -0,0 +1,19 @@
+package main
+
+import "fmt"
+
+func plus(a int, b int) int {
+	return a+b
+}
+
+func plusPlus(a, b, c int) int {
+	return a + b + c
+}
+
+func main() {
+	res := plus(1, 2)
+	fmt.Println("1+2 =", res)
+	
+	res = plusPlus(1, 2, 3)
+	fmt.Println("1+2+3 =", res)
+}

gobyexample/multiple-return-values.go

@@ -0,0 +1,16 @@
+package main
+
+import "fmt"
+
+func  vals() (int, int) {
+	return 3,7
+}
+
+func main() {
+	a,b := vals()
+	fmt.Println(a)
+	fmt.Println(b)
+
+	_, c := vals()
+	fmt.Println(c)
+}

gobyexample/range.go

@@ -0,0 +1,31 @@
+package main
+
+import "fmt"
+
+func main() {
+	nums := []int{2, 3, 4}
+	sum := 0
+	for _, num := range nums {
+		sum += num
+	}
+	fmt.Println("sum:",sum)
+
+	for i,num := range nums {
+		if num == 3 {
+			fmt.Println("index:",i)
+		}
+	}
+
+	kvs := map[string]string{"a":"apple", "b":"banana"}
+	for k, v := range kvs {
+		fmt.Printf("%s -> %s\n", k, v)
+	}
+	
+	for k := range kvs {
+		fmt.Println("key:", k)
+	}
+
+	for i,c := range "go" {
+		fmt.Println(i,c)
+	}
+}

gobyexample/recursion.go

@@ -0,0 +1,25 @@
+package main
+
+import "fmt"
+
+func fact(n int) int {
+	if n==0 {
+		return 1
+	}
+	return n * fact(n-1)
+}
+
+func main() {
+	fmt.Println(fact(7))
+
+	var fib func(n int) int
+
+	fib = func(n int) int {
+		if n<2 {
+			return n
+		}
+		return fib(n-1) + fib(n-2)
+	}
+
+	fmt.Println(fib(7))
+}

gobyexample/variadic-functions.go

@@ -0,0 +1,20 @@
+package main
+
+import "fmt"
+
+func sum(nums ...int) {
+	fmt.Print(nums, " ")
+	total := 0
+	for _, num := range nums {
+		total += num
+	}
+	fmt.Println(total)
+}
+
+func main() {
+	sum(1,2)
+	sum(1,2,3)
+
+	nums := []int{1, 2, 3, 4}
+	sum(nums...)
+}

hello/hello.go

@@ -1,7 +1,11 @@
 package main
 
-import "fmt"
+import (
+        "fmt"
+        "c.infdj.com/GO/courses_golang/hello/morestrings"
+)
 
 func main() {
-	fmt.Println("Hello, world.")
+        // fmt.Println("Hello, world.")
+        fmt.Println(morestrings.ReverseRunes("!oG ,olleH"))
 }

hello/morestrings/reverse.go

@@ -0,0 +1,12 @@
+// Package morestrings implements additional functions to manipulate UTF-8
+// encoded strings, beyond what is provided in the standard "strings" package.
+package morestrings
+
+// ReverseRunes returns its argument string reversed rune-wise left to right.
+func ReverseRunes(s string) string {
+	r := []rune(s)
+	for i, j := 0, len(r)-1; i < len(r)/2; i, j = i+1, j-1 {
+		r[i], r[j] = r[j], r[i]
+	}
+	return string(r)
+}

hello/morestrings/reverse_test.go

@@ -0,0 +1,19 @@
+package morestrings
+
+import "testing"
+
+func TestReverseRunes(t *testing.T) {
+	cases := []struct {
+		in, want string
+	}{
+		{"Hello, world", "dlrow ,olleH"},
+		{"Hello, 世界", "界世 ,olleH"},
+		{"", ""},
+	}
+	for _, c := range cases {
+		got := ReverseRunes(c.in)
+		if got != c.want {
+			t.Errorf("ReverseRunes(%q) == %q, want %q", c.in, got, c.want)
+		}
+	}
+}