+ 1

Mobile IDEs?

Why do mobile IDEs seem to not work properly? I've tried CPP N-IDE and C Mobile and both seem to handle this code incorrectly: #include <iostream> using namespace std; int main() { unsigned long long int n,x = 0; for(x=2;x<40;x=x+2){ n=2<<x; cout << x << " : " << n << endl ; } } Seems to just output 0 for all numbers past 31 Why does this happen? Is there an offline mobile IDE that works properly?

25th Mar 2019, 10:23 PM
Daniel Cooper
Daniel Cooper - avatar
2 Antworten
+ 7
I use Termux with clang package installed. The output for your code appears to be similar to Code Playground's. https://play.google.com/store/apps/details?id=com.termux Anyway, it looks like n would overflow for 2 << x where x > 31. This should be causing the 0 values on the IDEs you mentioned. The mobile compilers are actually working fine: Overflow is, after all, undefined behaviour and the results are dependent on compiler implementation. https://stackoverflow.com/questions/16188263/is-signed-integer-overflow-still-undefined-behavior-in-c
25th Mar 2019, 10:48 PM
Hatsy Rei
Hatsy Rei - avatar
25th Mar 2019, 11:28 PM
Calviղ
Calviղ - avatar