why this would result in long integer overflow

Question

I checked the document that long= int64 has range more than 900,000,000,000,000

Here is my code:

int r = 99;
long test1 = r*r*r         


        

Answer 1

As the other have said, but:

long test2 = 99L * 99 * 99 * 99 * 99;

This will give you the correct result with less L around :-)

This happens because the first 99L is a long, so all the multiplications are done in the long "field" and all the other integers are upcasted to long before the multiplication (clearly the multiplication is always between 2 numbers and it's from left to right, so it's like (((99L * 99) * 99) * 99) * 99 and each "partial" result is a long and causes the next operand to be converted to long.)