/in/foo.cc: In function 'int main()':
/in/foo.cc:10:7: error: 'snm' was not declared in this scope
   sum=snm*10+x%10;
       ^~~
/in/foo.cc:6:8: warning: unused variable 'y' [-Wunused-variable]
  int x,y,sum=0;
        ^