Func Golang

gistfile1.txt

func hypot(x, y float64) float64 {
         return math.Sqrt(x*x + y*y)
}
fmt.Println(hypot(3, 4)) // "5"
x and y are parameters in the declaration, 3 and 4 are arguments of the call, and the function returns a float64 value.

Arguments are passed by value, so the function receives a copy of each argument; 
modifica- tions to the copy do not affect the caller. However, if the argument contains some kind of ref- erence, 
like a pointer, slice, map, function, or channel, then the caller may be affected by any modifications the function 
makes to variables indirectly referred to by the argument.

You may occasionally encounter a function declaration without a body, 
indicating that the function is implemented in a language other than Go. 
Such a declaration defines the function signature.package math
     func Sin(x float64) float64 // implemented in assembly language