Java Loop help

Question

Maybe a more advanced learner can help me with this problem:
public class WhileLoop {
public static void main(String[] args) {
int r = 1;
int i = 1;
while(i < 65) {
r = r*2;
i++;
}
System.out.println(r);
}
}

//Why is the output 0???

Answer 1

That's because result is out of int range (also result is out of long range).
You need BigInteger to resolve this problem :

https://code.sololearn.com/cKKLqJ24bjhu/?ref=app

Answer 2

Correcting the line : System.out.println(r);

Mathematically answer is 2^64.

But as java cannot store such a big number. Output will be something different maybe 0.

Answer 3

your doubling the previous value of r each loop like @cHiRag said its such a big number. You could always limit your while loop say too i<20 ?