How Golang functions handle return results

Go functions can return results through the return statement, and the return result type is determined by the last parameter list in the function signature. Methods for processing returned results include: No return result: No processing required. Single return value: assigned to a variable using the assignment operator. Multiple return values: Use multiple variables to receive, in the same order as the function signature. Named field return value: Use the named field to return the structure and specify the field name to obtain the value.

Processing of return results in Go functions

In the Go language, a function can return one or more results through the return statement value. The type of result returned is determined by the last parameter list in the function signature.

There are several methods to handle the return result of the function:

No return result

func greet() {
    fmt.Println("Hello, world!")
}

The above function does not return a result, so there is no need to process it.

Single return value

func getGreeting() string {
    return "Hello, world!"
}

// 使用方式
greeting := getGreeting()
fmt.Println(greeting) // 输出: Hello, world!

For a single return value, you can use the assignment operator to assign it to a variable.

Multiple return values

func getGreetingAndCount() (string, int) {
    return "Hello, world!", 1
}

// 使用方式
greeting, count := getGreetingAndCount()
fmt.Println(greeting, count) // 输出: Hello, world! 1

For multiple return values, multiple variables can be used to receive them. The values ​​are in the same order as they appear in the function signature.

Named field return value

You can return a structure by using a named field:

type Person struct {
    Name string
    Age  int
}

func getPerson() Person {
    return Person{Name: "John", Age: 30}
}

// 使用方式
person := getPerson()
fmt.Println(person.Name, person.Age) // 输出: John 30

When using a named field to return a structure, you can specify the field name to obtain it. corresponding value.

Practical case

Command line parameter processing

package main

import (
    "fmt"
    "os"
)

func main() {
    args := os.Args

    if len(args) == 1 {
        fmt.Println("用法: myprogram name age")
        return
    }

    name := args[1]
    age, err := strconv.Atoi(args[2])
    if err != nil {
        fmt.Println("年龄必须是数字")
        return
    }

    fmt.Printf("欢迎使用 myprogram, %s (%d 岁)\n", name, age)
}

In this example, the main function passes os. Args slice takes command line arguments and uses multiple variables to process them. If there are missing or malformed arguments, use the return statement to exit the program.

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