Exam Battle: One-stop solution to Go language exam problems

"Exam Battle: One-stop solution to Go language exam problems, specific code examples are required"

As an efficient and concise programming language, Go language is becoming more and more popular. It has become more and more popular among programmers. However, when dealing with exams, sometimes we may encounter some problems that require a deeper understanding and mastery of Go language knowledge to solve. This article will focus on some common Go language exam problems, combined with specific code examples, to help readers better understand and deal with these problems.

1. The difference between slices and arrays

Slices and arrays are two commonly used data structures in the Go language, but there are obvious differences between them. The length of an array is determined when it is declared, while the length of a slice changes dynamically. The following is a code example to illustrate the difference between the two:

package main

import "fmt"

func main() {
    // 声明一个数组
    arr := [3]int{1, 2, 3}
    // 声明一个切片
    slice := []int{1, 2, 3}

    // 输出数组和切片的长度
    fmt.Println("数组的长度：", len(arr))
    fmt.Println("切片的长度：", len(slice))
}

In the above code example, we declare an array of length 3 arr and an array containing 3 elements sliceslice, and then output their lengths respectively. By running this code, you can see that the length of the array is determined when it is declared, and the length of the slice changes dynamically based on the number of elements.

2. Use of the defer keyword

#The defer keyword is used to delay the execution of functions, and is usually used in scenarios such as resource release and file closing. The execution order of defer statements is opposite to the order in which they appear, that is, the statements following defer are executed first. The following is an example to demonstrate the use of defer:

package main

import "fmt"

func main() {
    defer fmt.Println("defer 1")
    defer fmt.Println("defer 2")
    fmt.Println("main function")
}

In the above code example, we use the defer keyword to delay printing two pieces of information, and then print main function. By running this code, you can see that the execution order of the defer statement is last in, first out, that is, "defer 2" is printed first, then "defer 1", and finally "main function" is printed.

3. The use of Goroutine

Goroutine is the concept of lightweight threads in the Go language, which can realize concurrent programming and improve program performance. The following is a simple example to demonstrate the use of Goroutine:

package main

import (
    "fmt"
    "time"
)

func printNumbers() {
    for i := 0; i < 5; i++ {
        time.Sleep(time.Second)
        fmt.Println(i)
    }
}

func main() {
    go printNumbers()
    fmt.Println("main function")
    time.Sleep(5 * time.Second)
}

In the above code example, we define a printNumbers function, which will output 5 numbers from 0 to 4 , and it will sleep for 1 second every time a number is output. In the main function, we use the go keyword to start a new Goroutine to execute the printNumbers function, and then print "main function" in the main thread. By running this code, you can see that the main thread and Goroutine are executed concurrently, and the output results will appear alternately.

Through the above examples, we have a deeper understanding of some basic knowledge and common problems of the Go language. When preparing for exams, in addition to mastering theoretical knowledge, it is also very important to practice and understand through actual code examples. I hope this article can help readers better prepare and face the challenges in the Go language exam.

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