Functions

// a function that takes in 2 ints and returns an int
func sum(x int, y int) int {
  return x + y
}

In Go, functions can have multiple return values. If we choose to write our functions with 2 return vlaues, then we must be sure to always return all of them.

• notice below that in the error case, we are still returning 0 as our first return value.

import "errors", "math"

func sqrt(x float64) (float64, error) {
  // logic: square root of a negative number throws an error
  if x < 0 {
    return 0, errors.New("Cannot get square root of negative number")
  }
  return math.Sqrt(x), nil
}

sqrtOf16, err := sqrt(16)
if err != nil {
  fmt.Println(err)
} else {
  fmt.Println(sqrtOf16)
}

In Go function, if we specify the result parameters (ie. return value(s)), then we can just specify return without any value/expression list following it.

• the result parameters act as ordinary local variables. They can be modified, and we can return (again, with nothing after) and our function will return those same result parameters:

// short-form
func a()(x float64, err error){
    x = 7.0
    // `return` here will return bother a and b, 
    // since that is what is specified above in the result parameters
    return
}
// long-form
func a() (float64,error){
  x := 7.0
  var err error
  return x,err
}

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Children

1. Methods