Add task2 in go

Author: Holger Lösken

src/go/t2/s1.go

@@ -0,0 +1,36 @@
+package main
+
+import "strconv"
+
+func NumberToOrdinal(number int) string {
+	if number == 0 {
+		return "0"
+	}
+
+	special := []int{11, 12, 13}
+	_, found := Find(special, number % 100)
+
+	ending := "th"
+
+	if !found {
+		switch number % 10 {
+		case 1:
+			ending = "st"
+		case 2:
+			ending = "nd"
+		case 3:
+			ending = "rd"
+		}
+	}
+
+	return strconv.Itoa(number) + ending
+}
+
+func Find(slice []int, val int) (int, bool) {
+	for i, item := range slice {
+		if item == val {
+			return i, true
+		}
+	}
+	return -1, false
+}

src/go/t2/s1_test.go

@@ -0,0 +1,30 @@
+package main
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestNumberToOrdinal(t *testing.T) {
+	type test struct {
+		input int
+		want  string
+	}
+
+	tests := []test{
+		{input: 1, want: "1st"},
+		{input: 2, want: "2nd"},
+		{input: 3, want: "3rd"},
+		{input: 4, want: "4th"},
+		{input: 11, want: "11th"},
+		{input: 21, want: "21st"},
+		{input: 22, want: "22nd"},
+	}
+
+	for _, tc := range tests {
+		got := NumberToOrdinal(tc.input)
+		if !reflect.DeepEqual(tc.want, got) {
+			t.Fatalf("expected: %v, got: %v", tc.want, got)
+		}
+	}
+}