


Go Pointers: What's the Difference Between `&` (Address-of) and `*` (Dereference)?
& and * Pointers
In Go, passing variables as function arguments can sometimes trigger compiler errors, which can be resolved by using pointers. However, the distinctions between & and * pointers often lead to confusion. This article aims to clarify the differences and usage scenarios for both pointer types.
Addressing the Error
In your example, the error is likely due to the mismatch between the expected argument type and the actual variable passed. The Decode function requires an address or pointer to a User struct, but you are passing the value directly. To resolve this, you can use the & operator to obtain the address of the User variable:
if err := decoder.Decode(&u); err != nil { http.Error(rw, "could not decode request", http.StatusBadRequest) return }
Understanding Pointers
Pointers are variables that hold addresses of other variables. The & operator returns the address of a variable, while the * operator allows us to access the value at that address.
In the example above, &u gives the address of the User struct, which is then passed to the Decode function that expects a pointer.
However, if you had created the User instance using:
u := new(User)
Then u would already be a pointer, and the & operator would not be necessary. You could also explicitly create a pointer using:
var u *User
Difference between & and *
The key difference between & and * is that * represents a redirection to the value stored at the address, while & returns the address itself.
Example:
var y int var pointerToY *int var pointerToPointerToInt **int y = 10 pointerToY = &y pointerToPointerToInt = &pointerToY
Now:
- y holds the value 10.
- *pointerToY redirects to y and prints its value 10.
- &y returns the address of y.
- &pointerToY returns the address of pointerToY.
- &pointerToPointerToInt returns the address of pointerToPointerToInt.
- **pointerToPointerToInt prints the value 10 since it redirects twice to get to y.
Usage Scenarios
& (Address-of Operator):
- To pass the address of a variable to a function.
- To obtain the address before assigning to a pointer.
- To compare two pointers.
Example:
func swap(x, y *int) { *x, *y = *y, *x }
* (Dereference Operator):
- To access the value stored at an address.
- To assign a value to a pointer.
- To compare two pointers.
Example:
var p *int *p = 10
Conclusion:
Understanding & and pointers is crucial in Go for efficient variable handling and addressing compiler errors. The key distinction lies in the 'redirect' behavior of , while & returns the actual address of the variable. By carefully considering the intended usage scenarios, you can effectively leverage pointers in your Go code for optimal performance and correctness.
The above is the detailed content of Go Pointers: What's the Difference Between `&` (Address-of) and `*` (Dereference)?. For more information, please follow other related articles on the PHP Chinese website!

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 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 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 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 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.

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.

ChooseGolangforhighperformanceandconcurrency,idealforbackendservicesandnetworkprogramming;selectPythonforrapiddevelopment,datascience,andmachinelearningduetoitsversatilityandextensivelibraries.

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.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

WebStorm Mac version
Useful JavaScript development tools

SAP NetWeaver Server Adapter for Eclipse
Integrate Eclipse with SAP NetWeaver application server.

MinGW - Minimalist GNU for Windows
This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.

Atom editor mac version download
The most popular open source editor