4.5.2.5.md

eBook/exercises/chapter_4/count_characters.go

@@ -0,0 +1,22 @@
+package main
+
+import (
+	"fmt"
+	"unicode/utf8"
+)
+
+func main() {
+	// count number of characters:
+	str1 := "asSASA ddd dsjkdsjs dk"
+	fmt.Printf("The number of bytes in string str1 is %d\n",len(str1))
+	fmt.Printf("The number of characters in string str1 is %d\n",utf8.RuneCountInString(str1))
+	str2 := "asSASA ddd dsjkdsjsこん dk"
+	fmt.Printf("The number of bytes in string str2 is %d\n",len(str2))
+	fmt.Printf("The number of characters in string str2 is %d",utf8.RuneCountInString(str2))
+}
+/* Output:
+The number of bytes in string str1 is 22
+The number of characters in string str1 is 22
+The number of bytes in string str2 is 28
+The number of characters in string str2 is 24
+*/

eBook/exercises/chapter_4/divby0.go

@@ -0,0 +1,8 @@
+package main
+
+func main() {
+	a, b := 10, 0
+	c := a / b // panic: runtime error: integer divide by zero
+
+	print(c)
+}

eBook/exercises/chapter_4/function_calls_function.go

@@ -0,0 +1,18 @@
+package main
+
+var a string  // global scope
+
+func main() {
+	a = "G"
+	print(a)
+	f1()
+}
+func f1() {
+	a := "O"   // new local variable a, only scoped within f1() !
+	print(a)
+	f2()
+}
+func f2() {
+	print(a)   // global variable is taken
+}
+// GOG

eBook/exercises/chapter_4/global_scope.go

@@ -0,0 +1,19 @@
+package main
+
+var a = "G" // global scope
+
+func main() {
+	n()
+	m()
+	n()
+}
+
+func n() {
+	print(a)
+}
+
+func m() {
+	a = "O" // simple assignment: global a gets a new value
+	print(a)
+}
+// GOO

eBook/exercises/chapter_4/local_scope.go

@@ -0,0 +1,17 @@
+package main
+
+var a = "G"   // global (package) scope
+
+func main() {
+	n()
+	m()
+	n()
+}
+func n() {
+	print(a)
+}
+func m() {
+	a := "O"  // new local variable a is declared
+	print(a)
+}
+// GOG