What is an error in Go? How to handle errors?

In Go, error is a built-in interface that represents an error as a value with an Error() string method. Error handling in Go is based on explicit checking of the error return value after calling a function. Instead of exceptions, a pattern is used where a function returns a result and an error, and the calling code checks whether the error is nil.

Example of error handling:

package main
import (
    "errors"
    "fmt"
)

func divide(a, b float64) (float64, error) {
    if b == 0 {
        return 0, errors.New("division by zero")
    }
    return a / b, nil
}

func main() {
    result, err := divide(10, 0)
    if err != nil {
        fmt.Println("Error:", err)
        return
    }
    fmt.Println("Result:", result)
}

This approach makes errors explicit and allows flexible handling.