How to concat a string and float64 in Go?

Question

I am trying to solve this: http://tour.golang.org/#58

Here is what I have done:

#imports omitted
type ErrNegativeSqrt float64

func (e ErrNegativeSqrt) Error() string {
    return "Cannot Sqrt negative number: " + string(e)
}

func Sqrt(f float64) (float64, error) {
    if f < 0 {
        return 0, ErrNegativeSqrt(1)
    }
    # calculate z here...
    return z, nil
}
# main omitted

I have also tried e.String() and e.string() but those didn't work too.

ANisus · Accepted Answer · 2012-08-31 20:21:28Z

10

Try using the fmt package

import "fmt"
...
return fmt.Sprint("Cannot Sqrt negative number ", float64(e))

answered Aug 31, 2012 at 20:21

ANisus

78.7k32 gold badges171 silver badges166 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

yasar Over a year ago

Thanks a lot. I had to use it with float64(e) as hints suggested, otherwise it made an infinite loop. I am not sure why though.

ANisus Over a year ago

Ah, yes. Forgot about that. fmt.Print (and other fmt functions) will print the error message of the type if it implement the error interface (has a method Error() string). This will cause fmt.Sprint to call your Error() func, which will call fmt.Sprint, etc, in a loop

Collectives™ on Stack Overflow

How to concat a string and float64 in Go?

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related