/in/foo.cc: In function 'int zdgys(int, int)':
/in/foo.cc:7:10: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
    7 |  while(r = a % b )
      |        ~~^~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:24:23: error: 'strlen' was not declared in this scope
   24 |   for (int j = 2; j < strlen(s); j++)
      |                       ^~~~~~
/in/foo.cc:3:1: note: 'strlen' is defined in header '<cstring>'; did you forget to '#include <cstring>'?
    2 | #include<cmath>
  +++ |+#include <cstring>
    3 | using namespace std;
/in/foo.cc:35:11: warning: ignoring return value of 'int system(const char*)', declared with attribute warn_unused_result [-Wunused-result]
   35 |     system("pause");
      |     ~~~~~~^~~~~~~~~