golang compilation error: 'undefined: io.WriteString' How to solve it?

Golang is a fast, reliable and efficient programming language. It compiles and runs very fast, so it is widely used in cloud computing, distributed systems, network programming and other fields. However, when writing code in Golang, you will also encounter some compilation errors. One of them is the "undefined: io.WriteString" error. This article will introduce the cause and solution of this error.

Error reason:
When you are writing code in Golang, if you use the io.WriteString function, but the io package is not imported into your code package, or the function is not used in your code, Then the "undefined: io.WriteString" error will occur during compilation. This is because the function is not defined in the code.

Workaround:
To resolve this error, you need to take the following steps:

1. Import io package

In your code, First you need to import the io package. You can import the io package using the following line of code:

import "io"

2. Use the io.WriteString function

Next, you need to The io.WriteString function is used in the code to write data in a string or byte slice. Following are some common examples of io.WriteString function.

Write the string into the file:

package main

import (

"fmt"
"io"
"os"

)

func main() {

file, err := os.Create("output.txt")
if err != nil {
    fmt.Println(err)
    return
}
defer file.Close()

str := "Hello, World!

"

_, err = io.WriteString(file, str)
if err != nil {
    fmt.Println(err)
}

}

Write byte slices to the file:

package main

import (

"fmt"
"io"
"os"

)

func main() {

file, err := os.Create("output.txt")
if err != nil {
    fmt.Println(err)
    return
}
defer file.Close()

var bytes = []byte{72, 101, 108, 108, 111, 44, 32, 87, 111, 114, 108, 100, 33, 10}
_, err = io.WriteString(file, string(bytes))
if err != nil {
    fmt.Println(err)
}

}

3. Recompile the code

Finally, you need Rerun the code to ensure that the io package has been imported correctly and the io.WriteString function has been used. During execution, if other compilation errors or runtime errors occur, you can solve them according to the error prompts.

Conclusion:
"undefined: io.WriteString" is a kind of Golang compilation error. Its reason is that the io.WriteString function is not defined in the code. To solve this error, you need to import the io package first, and then use io in the code .WriteString function. Using these steps can help you avoid this error and make your code more robust and reliable.

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