Variable scope of golang function return value

The return value variable of a Golang function only exists inside the function and is destroyed after the function is executed. 1. The scope of variables is limited to the inside of the function, for example, the result variable in the multiply function. 2. The main function can access the return value of the function. For example, the avg variable returned by the calculateAvg function is available in the main function.

Golang function return value variable scope

In Golang, the scope of the function return value variable is limited to the function. These variables will be destroyed after the function is executed.

Variable scope example

The following example demonstrates the scope of a function return value variable:

package main

import "fmt"

func main() {
    // 在 main 函数中声明一个变量
    x := 10

    // 将 x 作为参数传递给 multiply 函数
    y := multiply(x, 5)

    // 在 main 函数中使用 y
    fmt.Println(y) // 输出：50
}

// multiply 函数返回 x * factor 的结果
func multiply(x, factor int) int {
    // 在 multiply 函数中声明一个变量
    result := x * factor

    // 返回 result
    return result
}

Practical case

Consider a function that calculates an average :

package main

import "fmt"

func main() {
    // 声明一个 []int 类型的 slice
    numbers := []int{1, 2, 3, 4, 5}

    // 计算平均数
    avg := calculateAvg(numbers)

    // 在 main 函数中使用 avg
    fmt.Println(avg) // 输出：3
}

// calculateAvg 函数计算给定 slice 的平均数并返回结果
func calculateAvg(numbers []int) float64 {
    // 在 calculateAvg 函数中声明一个变量
    sum := 0

    // 计算总和
    for _, num := range numbers {
        sum += num
    }

    // 计算平均数
    avg := float64(sum) / float64(len(numbers))

    // 返回 avg
    return avg
}

In this example, the avg variable is declared inside the calculateAvg function. Therefore, once the function execution is completed, the avg variable and its value will be destroyed. However, because we used the return value of avg in the main function, we can still access this value in the main function.

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