C++ : integer constant is too large for its type

Question

I need to bruteforce a year for an exercise. The compiler keep throwing this error:

bruteforceJS12.cpp:8:28: warning: integer constant is too large fo

Answer 1

A quick way to figure out the numeric limits on your system would be to use std::numeric_limits. The output on my system when I run the following code:

#include <iostream>
#include <limits>

int main()
{   
     std::cout << "ull\t"
              << std::numeric_limits<unsigned long long>::lowest() << '\t'
              << std::numeric_limits<unsigned long long>::max() << std::endl ;
}

is:

ull 0   18446744073709551615

we can see the max value is definitely smaller than your literal value:

 18446744073709551615
 318338237039211050000

So your integer literal is just too large for unsigned long long type.

Answer 2

Your problem is simply that 318338237039211050000ULL is out of range.

Assuming a 64 bit type, a 64 bit value is good for log10( 2⁶⁴-1) decimal digits (i.e. all 19 digit values and some lower 20 digit values), 318338237039211050000ull has 21 digits. 2⁶⁴-1 (18446744073709551615ull) is the maximum.

The value 318338237039211050000 requires at least log10(318338237039211050000)/log10(2) bits. That's 69 bits.