Go Language exercise:errors

This is a creation in Article, where the information may have evolved or changed.

Copy your Sqrt function from the earlier exercises and modify it to return an error value.

SqrtShould return a Non-nil error value when given a negative number, as it doesn ' t support complex numbers.

Create a new type

Type errnegativesqrt float64

and make it error a by giving it a

Func (e errnegativesqrt) Error () string

Method such that ErrNegativeSqrt(-2).Error() returns "cannot Sqrt negative number: -2" .

Note: a call to inside the method would send the program into an fmt.Print(e) Error infinite loop. You can avoid this by converting first e : fmt.Print(float64(e)) . Why?

Change your Sqrt function to return the ErrNegativeSqrt value when given a negative number.

Package Main

Import (
"FMT"
)

Type errnegativesqrt float64

Func (e errnegativesqrt) Error () string{
Return to FMT. Sprintf ("Cantnot Sqrt negative Number:%v", Float64 (e))
}

Func Sqrt (f float64) (Float64, error) {
If f < 0 {
return 0, errnegativesqrt (f)
}
Z: = f
For I: = 0; I < 10; i++ {
z = (z + f/z)/2
}
Return Z, Nil
}

Func Main () {
If value, err: = Sqrt (-2); Err! = Nil {
Fmt. PRINTLN (ERR)
} else {
Fmt. Println (value)
}
If value, err: = Sqrt (2); Err! = Nil {
Fmt. PRINTLN (ERR)
} else {
Fmt. Println (value)
}
}