/in/foo.cc: In function 'int main()':
/in/foo.cc:4:21: warning: unused variable 'j' [-Wunused-variable]
  double a,b,c,d,m,n,j;
                     ^
/in/foo.cc:15:9: warning: 'b' may be used uninitialized in this function [-Wmaybe-uninitialized]
   n=(m-c-d)/8;
     ~~~~^~~
/in/foo.cc:8:4: warning: 'm' may be used uninitialized in this function [-Wmaybe-uninitialized]
   m+=a;
   ~^~~