Why Does Math.pow(x,y) Count as a Double?

Question

I\'m writing a Java program to calculate how much food it will take to get a monster to a certain level in My Singing Monsters. When I run the program, it says, \"cannot con

Answer 1

Math.pow return double and you assigning double value to int this is why it is giving error. You have to downcast it. Like

int levelMeal = (int)5*(Math.pow(2,level-1));

Answer 2

I think there's typically hardware support on most modern processors for doing floating-point powers, but not integers. Because of that, for a general power, it's actually faster to do Math.power with a double and then convert it back to an int.

However, in this case there's a faster way to do it for ints. Since you're doing a power of 2, you can just use the bitwise left-shift operator instead:

int levelMeal = 5*(1<<(level-1));

As Rhymoid pointed out in his comment, that expression can be further simplified to remove the 1:

int levelMeal = 5<<(level-1);

Answer 3

You'll have to do this:

int levelMeal = (int) (5*(Math.pow(2,level-1)));
                  ^
           this is a cast

As you can see in the documentation, Math.pow() returns a double by design, but if you need an int then an explicit cast must be performed.