if条件语句
package main
import (
"fmt"
"io/ioutil"
)
func main() {
const filename = "abc.txt"
contents,err :=ioutil.ReadFile(filename)
if err == nil {
fmt.Println(err)
}else {
fmt.Printf("%s\n",contents)
}
}
运行结果如下:
创建一个abc.txt文件在执行
运行结果如下:
go语言的if可以像其他语言的for一样编写
func main() {
const filename = "abc.txt"
if contents,err :=ioutil.ReadFile(filename); err != nil{
fmt.Println(err)
}else {
fmt.Printf("%s\n",contents)
}
}
switch条件语句
switch会自动break,除非使用fallthrough,switch后面可以没有表达式
package main
import (
"fmt"
)
func grade(score int) string {
g :=""
switch {
case score < 0 || score > 100:
panic(fmt.Sprintf("Wrong Score: %d",score))
case score < 60:
g = "F"
case score < 80:
g = "C"
case score < 90:
g = "B"
case score <= 100:
g = "A"
}
return g
}
func main() {
fmt.Println(
grade(0),
grade(55),
grade(60),
grade(88),
grade(95),
grade(100),
grade(120),
)
}
运行结果如下: