/in/foo.cc: In function 'bool prime(int)':
/in/foo.cc:7:13: warning: statement has no effect [-Wunused-value]
    7 |         for(i;i<x;i++)
      |             ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:29:13: warning: statement has no effect [-Wunused-value]
   29 |         for(l;p>0;l++)
      |             ^
/in/foo.cc:40:13: warning: statement has no effect [-Wunused-value]
   40 |         for(n;n<l;n++)
      |             ^