Go语言基础教程之函数和方法详解

func functionName(parameterList) (returnTypeList) {
    // 函数体
}

package main
import "fmt"
// 定义一个简单的加法函数
func add(a int, b int) int {
    return a + b
}
func main() {
    result := add(3, 5)
    fmt.Println("3 + 5 =", result)  // 输出：3 + 5 = 8
}

package main
import "fmt"
// 返回两个数的和与差
func sumAndDiff(a, b int) (int, int) {
    sum := a + b
    diff := a - b
    return sum, diff
}
func main() {
    sum, diff := sumAndDiff(10, 5)
    fmt.Println("Sum:", sum, "Diff:", diff)  // 输出：Sum: 15 Diff: 5
}

package main
import "fmt"
// 使用命名返回值
func divide(a, b int) (quotient int, remainder int) {
    quotient = a / b
    remainder = a % b
    return
}
func main() {
    q, r := divide(10, 3)
    fmt.Println("Quotient:", q, "Remainder:", r)  // 输出：Quotient: 3 Remainder: 1
}

package main
import "fmt"
// 按值传递
func modifyValue(x int) {
    x = 100
}
func main() {
    a := 10
    modifyValue(a)
    fmt.Println("a after modifyValue:", a)  // 输出：a after modifyValue: 10
}

package main
import "fmt"
// 按指针传递
func modifyPointer(x *int) {
    *x = 100
}
func main() {
    a := 10
    modifyPointer(&a)
    fmt.Println("a after modifyPointer:", a)  // 输出：a after modifyPointer: 100
}

package main
import "fmt"
func main() {
    // 定义并调用匿名函数
    func() {
        fmt.Println("Hello from anonymous function!")
    }()
}

Hello from anonymous function!

package main
import "fmt"
// 返回一个闭包
func getCounter() func() int {
    count := 0
    return func() int {
        count++
        return count
    }
}
func main() {
    counter := getCounter()
    fmt.Println(counter()) // 输出 1
    fmt.Println(counter()) // 输出 2
    fmt.Println(counter()) // 输出 3
}

package main
import "fmt"
// 定义一个函数类型
type operation func(int, int) int
// 将函数作为参数
func compute(a, b int, op operation) int {
    return op(a, b)
}
func main() {
    sum := compute(3, 5, func(a, b int) int {
        return a + b
    })
    fmt.Println("Sum:", sum)  // 输出：Sum: 8
}

package main
import "fmt"
// 返回一个函数
func getMultiplier(factor int) func(int) int {
    return func(x int) int {
        return x * factor
    }
}
func main() {
    multiplyBy2 := getMultiplier(2)
    fmt.Println(multiplyBy2(5)) // 输出 10
}

type Age uint
func (age Age) String(){
    fmt.Println("the age is",age)
}

func main() {
    age:=Age(25)
    age.String()
}

the age is 25