/in/foo.cc: In function 'int main()':
/in/foo.cc:8:8: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   {if(a==-1) break;
        ^
/in/foo.cc:11:14: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
    {if(m=a%10) sum+=m*pow(2,n);
              ^