can you write a method that takes in an integer and checks to see if its a perfect square (ie returns a boolean value)?

ie 4 is a perfect square sqrt(4) = 2
2 is not a perfect square since sqrt(2) = not an int.


or is there a method that checks if something is an integer??

 

of course you can, and of course there is.

but checking if something is an integer would only apply to an object that is not already an integer, like a string or a double (probably going to be a double). i don't think there's a built in method to check whether an object is an integer or not, so you might have to do it yourself. should be pretty easy, tho. look up the java API:
http://java.sun.com/j2se/1.4.2/docs/api/

 

something like:

boolean SquareCheck(int x){

double y = sqrt(x);
int q = sqrt(x);
y = y * 10000000; //use however many decimal places the double
//could hold
x = x * 10000000;
if( (y-x) != 0) return false;
return true;
}

This would rely on the sqrt function merely truncating the value returned from the sqrt function, which I can't remember if that's what happens or not. I'm a little rusty.

 

public boolean perfectSquare(int anInteger)
{
boolean perfectSquare;
double theInteger = (double)anInteger;
double sqrt = sqrt(theInteger);

double perfectSquare = sqrt * sqrt;

if(theInteger == perfectSquare)
{
perfectSqaure = true;
}

else
{
perfectSquare = false;
}


return perfectSquare;

}


Something like that....include java.lang.Math

Check out http://java.sun.com/j2se/1.4.2/docs/api/index.html

 

man, you guys give the answer out way too easily. gotta make him think about it a little bit!

 

lol...yeah I was drunk last night h:

 

um.. how about..

if the mantissa of sqrt(x) == 0, then x is a perfect square. but you'd have to figure out what function gets the mantissa, which puts you in a similar spot.

 

i already got it last night h: thanks for the help anyways

 

are you sure that works? I thought that when you caste from a double to an int, it truncates, which would cause problems with the way you are doing it. Have you checked it on several different numbers?

 

it gave me the output i wanted..

i wanted to find 4 numbers where the sum of each pair is a perfect square .. it gave me some that werent .. but bleh it gave me lots that were.. i needed 1 set

im done