/in/foo.c: In function 'main':
/in/foo.c:6:11: warning: statement with no effect [-Wunused-value]
   q=0;p=0;g-0;
           ^
/in/foo.c:14:5: warning: implicit declaration of function 'abs' [-Wimplicit-function-declaration]
   x=abs(q-p)-1;
     ^~~
/in/foo.c:11:10: warning: 'g' may be used uninitialized in this function [-Wmaybe-uninitialized]
       if (g==0) {q=q+x;g=1;}
          ^