Question

that’s my code:

long base2(int number)
{
   long result = 0;
   int num = number;
   int multi = 1;
   int rem;
   while(num > 0)
   {
    rem = num % 2;
    result = result + (rem * multi);
    num = num / 2;
    multi = multi * 10;
   }
   return result;
}

I’m getting a weird print: -1884801888

I ran the debugger and its calculating properly but just at the end the final answer changes to this -1884801888

[The printing happens in the main, I checked, the number changes here to -1884801888]

Thank you!

Answer 1

On most common platforms nowadays, both int and long are 32 bits wide. You are causing an integer overflow, where the values you’re computing exceed the range representable in signed 32-bit integers.

If the values don’t fit in 32 bits but do fit in 63 or 64 bits, you can use long long or unsigned long long (or the fixed-width types int64_t or uint64_t from <stdint.h>) data types to store the result. If those aren’t big enough, then you’ll need to use a more complicated solution (e.g. the GMP library has arbitrary-sized integer support), but only do that as a last resort.