error object is returned.
func divide(number1, number2 int) (int, error) {
if number2 == 0 {
return 0, errors.New("cannot divide by 0")
}
return number1/number2, nil
}
func main() {
result,err := divide(1,2)
if err != nil {
log.Fatal(err)
}
fmt.Println(result)
}
// This iterface needs to be implemented
/*
type error interface {
Error() string
}
*/
type DivideByZeroErr struct{
num1 int
num2 int
}
func (err *DivideByZeroErr) Error() string {
return fmt.Sprintf("cannot divide %d by 0", err.num1)
}
func divide(number1, number2 int) (int, error) {
if number2 == 0 {
return 0, &DivideByZeroErr{number1, number2}
}
return number1/number2, nil
}
func main() {
result,err := divide(1,0)
if err != nil {
log.Fatal(err)
}
fmt.Println(result)
}
// output
// cannot divide 1 by 0
Basically when an error occurs there is a situation where one would want the application to stop if not succeded. some use cases are, Initally making database connection or initlizing something for app to run and it fails.
Example: func MustCompile(str string) *Regexp 2
With the use of use case specific OBJECT_TYPE (replace OBJECT_TYPE with your required return type)
func Must(obj OBJECT_TYPE, err error) OBJECT_TYPE {
if err != nil {
panic(err)
}
return obj
}
With the use of generics 3
func Must[T any](obj T, err error) T {
if err != nil {
panic(err)
}
return obj
}