常量介绍

示例

package mainimport ("fmt"
)func main() {const name = "tom"fmt.Println(name)const tax float64 = 0.8fmt.Println(tax)
}

go run const.go 
tom
0.8

package mainimport ("fmt"
)func main() {const a intfmt.Println(a)
}

go run const.go 
# command-line-arguments
./const.go:8:8: missing init expr for a

package mainimport ("fmt"
)func getVal() {fmt.Printf("测试")
}
func main() {const b = 9 / 3fmt.Println(b)//const c = getVal()//fmt.Println(c)
}

go run const.go 
3

package mainimport ("fmt"
)func getVal() {fmt.Printf("测试")
}
func main() {//const b = 9 / 3//fmt.Println(b)const c = getVal()fmt.Println(c)
}

go run const.go 
# command-line-arguments
./const.go:13:12: getVal() (no value) used as value

package mainimport ("fmt"
)func getVal() {fmt.Printf("测试")
}
func main() {//const b = 9 / 3//fmt.Println(b)//const c = getVal()//fmt.Println(c)num := 9const b = num / 3fmt.Println(b)
}

go run const.go 
# command-line-arguments
./const.go:16:12: num / 3 (value of type int) is not constant

常量比较简单的写法

package mainimport ("fmt"
)func getVal() {fmt.Printf("测试")
}
func main() {const (a = 1b = 2)fmt.Println(a, b)const (c = iotade)fmt.Println(c, d, e)
}

go run const.go 
1 2
0 1 2