1.常量

package main

import "fmt"

// const 来定义枚举类型
const (
    // 可以在const() 添加一个关键字 iota, 每行的 iota 都会累加1
    BEIJINT  = 0
    SHANGHAI = 1
    SHENZHEN = 2
)

// main
func main() {
    const length int = 10
    fmt.Println("length = ", length)

    // length = 100 // 常量不可以被修改
    fmt.Println("BeiJing = ", BEIJINT)
    fmt.Println("ShangHai = ", SHANGHAI)
    fmt.Println("ShenZhen = ", SHENZHEN)

}

// 执行结果
length =  10
BeiJing =  0
ShangHai =  1
ShenZhen =  2

2.iota

package main

import "fmt"

// const 来定义枚举类型
const (
    // 可以在const() 添加一个关键字 iota, 每行的 iota 都会累加1,第一行的iota的默认值是0
    BEIJINT = iota    //iota = 0
    SHANGHAI          //iota = 1
    SHENZHEN          //iota = 2
)

// main
func main() {
    const length int = 10
    fmt.Println("length = ", length)

    // length = 100 // 常量不可以被修改
    fmt.Println("BeiJing = ", BEIJINT)
    fmt.Println("ShangHai = ", SHANGHAI)
    fmt.Println("ShenZhen = ", SHENZHEN)

}
// 执行结果
length =  10
BeiJing =  0
ShangHai =  1
ShenZhen =  2

示例2

package main

import "fmt"

// const 来定义枚举类型
const (
    // 可以在const() 添加一个关键字 iota, 每行的 iota 都会累加1,第一行的iota的默认值是0
    BEIJINT = 10 * iota  // iota = 0, beijing = 10 * 0 = 0
    SHANGHAI             // iota = 1, beijing = 10 * 1 = 10
    SHENZHEN            // iota = 2, beijing = 10 * 2 = 20
)

// main
func main() {
    const length int = 10
    fmt.Println("length = ", length)

    // length = 100 // 常量不可以被修改
    fmt.Println("BeiJing = ", BEIJINT)
    fmt.Println("ShangHai = ", SHANGHAI)
    fmt.Println("ShenZhen = ", SHENZHEN)

}
// 执行结果
length =  10
BeiJing =  0
ShangHai =  10
ShenZhen =  20

示例3

package main

import "fmt"

// const 来定义枚举类型
const (
    // 可以在const() 添加一个关键字 iota, 每行的 iota 都会累加1,第一行的iota的默认值是0
    a, b = iota + 1, iota + 2 // iota = 0 , a = 1, b = 2
    c, d                      // iota = 1 , c = 2, d = 3
    e, f                      // iota = 2 , e = 3, f = 4

    g, h = iota * 2, iota * 3 // iota = 3 , g = 6, h = 9
    i, k                      // iota = 4 , i = 8, k = 12
)

// main
func main() {
    fmt.Println("a = ", a, ", b = ", b)
    fmt.Println("c = ", c, ", d = ", d)
    fmt.Println("e = ", e, ", f = ", f)
    fmt.Println("g = ", g, ", h = ", h)
    fmt.Println("i = ", i, ", k = ", k)

}
// 执行结果
a =  1 , b =  2
c =  2 , d =  3
e =  3 , f =  4
g =  6 , h =  9
i =  8 , k =  12

3.总结

06.常量和iota_IT