Learn Golang in Day 8
变量作用域
局部变量
package main
import "fmt"
func main() {
/* 声明局部变量 */
var a, b, c int
/* 初始化参数 */
a = 10
b = 20
c = a + b
fmt.Printf("结果： a = %d, b = %d and c = %d\n", a,b,c)
}
全局变量
- 函数体之外定义的变量都是全局变量
- 全局变量可以在整个包作用域内使用，外部包使用时需要导出
package main
import "fmt"
/* 声明全局变量 */
var g int
func main() {
var a, b int
/* 初始化参数 */
a = 10
b = 20
g = a + b
fmt.Printf("result: a = %d, b = %d, g = %d\n", a , b, )
fmt.Printf("a and b is local variable , but g is global variable.\n")
}
形式参数 formal paramter
- 形式参数也是局部变量
- 对局部变量的修改，只对当前作用域有效
package main
import "fmt"
//全局变量
var a int = 20
func main() {
/* 局部变量 */
var a int = 10
var b int = 20
var c int = 0
fmt.Printf("a =%d in the main function.\n", a)
c = sum(a,b)
fmt.Printf("c = %d in the main function.\n", c)
fmt.Printf("a=%d, in main function.\n", a)
}
func sum(a, b int) int {
a++
fmt.Printf("a=%d, in sum function.\n", a)
fmt.Printf("b=%d, in sum function.\n", b)
return a + b
}