An article to talk about golang error types

Golang is a powerful programming language that has been loved by programmers since its birth. The error handling mechanism is also a very important module in Golang. This article will focus on Golang error types.

In Golang, the error type refers to a built-in interface type error. The custom error type we define needs to meet this interface before it can be processed using the error type. The error type is defined as follows:

type error interface {
    Error() string
}

The error type has only one method, the Error() method, which returns a string type error message. All error types in Golang must implement the error interface before they can be used as error types.

In addition to custom error types, Golang also predefines some common error types.

1. Common error types

Common error types refer to errors that do not require any additional information. In Golang, ordinary error types can be created using the errors.New() function. For example:

import "errors"  
func divideByZero(a, b int) (int, error) {  
    if b == 0 {
        return 0, errors.New("除数不能为0")  
    }
    return a / b, nil  
}

In the above code, if the divisor is 0, a common error type is returned, containing the string "The divisor cannot be 0".

2. Custom error types

Custom error types refer to error types that require additional information to be appended to the error message. In Golang, it can be defined in the following way:

type myError struct {  
    Op       string  
    Operand  string  
    message  string  
}  
func (e *myError) Error() string {  
    return fmt.Sprintf("%s %s %s", e.Op, e.Operand, e.message)  
}  
func operate(a, b int, op string) (int, error) {  
    if op != "+" && op != "-" && op != "*" && op != "/" {  
        return 0, &myError{"operate", op, "不支持的操作"}  
    }  
    if op == "/" && b == 0 {  
        return 0, &myError{"operate", op, "除数不能为0"}  
    }  
    var res int  
    switch op {  
    case "+":
        res = a + b  
    case "-":
        res = a - b  
    case "*":
        res = a * b  
    case "/":
        res = a / b  
    }  
    return res, nil  
}

In the above code, we define a custom error type myError, which contains operation and error information. And we implemented the Error() method to return an error message containing additional information. In the operation function, if the operation is not supported or the divisor is 0, a custom error type will be returned.

3. panic error type

In Golang, use the panic() function to throw an exception. At this time, the program will stop executing, and subsequent code will not be executed. The internal implementation of the panic() function actually creates a panic error type and triggers it. For example:

func factorial(n int) int {  
    if n < 0 {  
        panic("参数必须为非负整数")  
    }  
    if n == 0 {  
        return 1  
    }  
    return n * factorial(n-1)  
}

In the above code, if the parameter passed in is a negative number, the program will throw a panic error type and stop execution.

Error handling in the program is very important, it can ensure the stability and security of the program. Different types of errors are handled differently in Golang. Programmers need to choose the error type that suits them based on the actual situation.

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