search
HomeBackend DevelopmentGolangHow Does Go\'s Defer Keyword Work in Function Execution Order?

How Does Go's Defer Keyword Work in Function Execution Order?

Understanding the Functionality of Go's Defer Keyword

When working with Go, understanding the behavior of the defer keyword is crucial. This keyword allows developers to defer the execution of a function until the surrounding function returns. However, it's important to note that the function's value and parameters are evaluated when the defer statement executes.

Example: Evaluating Defer Order

To illustrate this, consider the following code:

<code class="go">package main

import "fmt"

func main() {
    defer having()(fun("with Go."))
    fmt.Print("some ") // evaluation order: 3
}

func having() func(string) {
    fmt.Print("Go ") // evaluation order: 1
    return funWithGo
}

func fun(msg string) string {
    fmt.Print("have ") // evaluation order: 2
    return msg
}

func funWithGo(msg string) {
    fmt.Println("fun", msg) // evaluation order: 4
}</code>

In this example, the code is executed in the following order:

  1. having function is evaluated and returns a function that takes a string as input (evaluation order: 1)
  2. fun function is evaluated with the "with Go." string as input (evaluation order: 2)
  3. fmt.Print("some ") is executed (evaluation order: 3)
  4. defer calls funWithGo function with the result from fun (evaluation order: 4)

Applying the Defer Principle

To resolve the issue mentioned in the original query, we can use the defer keyword to correctly print the ticket price based on the entered age. Below is a modified version of the code:

<code class="go">package main

import "fmt"

func main() {
    age := 999
    defer fmt.Println("Your age is:", getAge(&age)) // defer printing the age
    defer fmt.Println("Your ticket price is:", getTicketPrice(age)) // defer printing the ticket price
}

func getTicketPrice(age int) float64 {
    // Calculate ticket price based on age
    // logic can be customized here
    fmt.Println("...order is 2...")
    switch {
    case age  13 && age <p>In this modified code, we correctly leverage the defer keyword to ensure that the age and ticket price are printed after the respective functions have executed, resolving the initial issue.</p></code>

The above is the detailed content of How Does Go\'s Defer Keyword Work in Function Execution Order?. For more information, please follow other related articles on the PHP Chinese website!

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Golang and Python: Understanding the DifferencesGolang and Python: Understanding the DifferencesApr 18, 2025 am 12:21 AM

The main differences between Golang and Python are concurrency models, type systems, performance and execution speed. 1. Golang uses the CSP model, which is suitable for high concurrent tasks; Python relies on multi-threading and GIL, which is suitable for I/O-intensive tasks. 2. Golang is a static type, and Python is a dynamic type. 3. Golang compiled language execution speed is fast, and Python interpreted language development is fast.

Golang vs. C  : Assessing the Speed DifferenceGolang vs. C : Assessing the Speed DifferenceApr 18, 2025 am 12:20 AM

Golang is usually slower than C, but Golang has more advantages in concurrent programming and development efficiency: 1) Golang's garbage collection and concurrency model makes it perform well in high concurrency scenarios; 2) C obtains higher performance through manual memory management and hardware optimization, but has higher development complexity.

Golang: A Key Language for Cloud Computing and DevOpsGolang: A Key Language for Cloud Computing and DevOpsApr 18, 2025 am 12:18 AM

Golang is widely used in cloud computing and DevOps, and its advantages lie in simplicity, efficiency and concurrent programming capabilities. 1) In cloud computing, Golang efficiently handles concurrent requests through goroutine and channel mechanisms. 2) In DevOps, Golang's fast compilation and cross-platform features make it the first choice for automation tools.

Golang and C  : Understanding Execution EfficiencyGolang and C : Understanding Execution EfficiencyApr 18, 2025 am 12:16 AM

Golang and C each have their own advantages in performance efficiency. 1) Golang improves efficiency through goroutine and garbage collection, but may introduce pause time. 2) C realizes high performance through manual memory management and optimization, but developers need to deal with memory leaks and other issues. When choosing, you need to consider project requirements and team technology stack.

Golang vs. Python: Concurrency and MultithreadingGolang vs. Python: Concurrency and MultithreadingApr 17, 2025 am 12:20 AM

Golang is more suitable for high concurrency tasks, while Python has more advantages in flexibility. 1.Golang efficiently handles concurrency through goroutine and channel. 2. Python relies on threading and asyncio, which is affected by GIL, but provides multiple concurrency methods. The choice should be based on specific needs.

Golang and C  : The Trade-offs in PerformanceGolang and C : The Trade-offs in PerformanceApr 17, 2025 am 12:18 AM

The performance differences between Golang and C are mainly reflected in memory management, compilation optimization and runtime efficiency. 1) Golang's garbage collection mechanism is convenient but may affect performance, 2) C's manual memory management and compiler optimization are more efficient in recursive computing.

Golang vs. Python: Applications and Use CasesGolang vs. Python: Applications and Use CasesApr 17, 2025 am 12:17 AM

ChooseGolangforhighperformanceandconcurrency,idealforbackendservicesandnetworkprogramming;selectPythonforrapiddevelopment,datascience,andmachinelearningduetoitsversatilityandextensivelibraries.

Golang vs. Python: Key Differences and SimilaritiesGolang vs. Python: Key Differences and SimilaritiesApr 17, 2025 am 12:15 AM

Golang and Python each have their own advantages: Golang is suitable for high performance and concurrent programming, while Python is suitable for data science and web development. Golang is known for its concurrency model and efficient performance, while Python is known for its concise syntax and rich library ecosystem.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
1 months agoBy尊渡假赌尊渡假赌尊渡假赌
R.E.P.O. Best Graphic Settings
1 months agoBy尊渡假赌尊渡假赌尊渡假赌
Will R.E.P.O. Have Crossplay?
1 months agoBy尊渡假赌尊渡假赌尊渡假赌

Hot Tools

PhpStorm Mac version

PhpStorm Mac version

The latest (2018.2.1) professional PHP integrated development tool

SAP NetWeaver Server Adapter for Eclipse

SAP NetWeaver Server Adapter for Eclipse

Integrate Eclipse with SAP NetWeaver application server.

SublimeText3 English version

SublimeText3 English version

Recommended: Win version, supports code prompts!

Atom editor mac version download

Atom editor mac version download

The most popular open source editor

Dreamweaver Mac version

Dreamweaver Mac version

Visual web development tools