Golang函数返回错误值处理完整示例

func divide(a, b float64) (float64, error) {
    if b == 0 {
        return 0, fmt.Errorf("cannot divide by zero")
    }
    return a / b, nil
}

result, err := divide(10, 2)
if err != nil {
    fmt.Println("Error:", err)
    return
}
fmt.Printf("Result: %.2f\n", result)

type DivideError struct {
    x, y float64
}

func (e *DivideError) Error() string {
    return fmt.Sprintf("division error: divide %.2f by %.2f", e.x, e.y)
}

func safeDivide(a, b float64) (float64, error) {
    if b == 0 {
        return 0, &DivideError{x: a, y: b}
    }
    return a / b, nil
}

result, err := safeDivide(5, 0)
if err != nil {
    if divErr, ok := err.(*DivideError); ok {
        fmt.Println("Custom error:", divErr.Error())
    } else {
        fmt.Println("Unknown error:", err)
    }
    return
}

_, err := divide(10, 0)
if err != nil {
    return fmt.Errorf("operation failed: %w", err)
}