/in/foo.cc: In function 'int main()':
/in/foo.cc:9:17: warning: left operand of comma operator has no effect [-Wunused-value]
  for (int i=a;i,b;i++)
                 ^
/in/foo.cc:12:8: warning: variable 'ii' set but not used [-Wunused-but-set-variable]
    int ii=i,jj=j;
        ^~
/in/foo.cc:22:8: warning: 'sum' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<sum<<endl;
        ^~~