/in/foo.cc: In function 'int main()':
/in/foo.cc:47:16: warning: 'ch' may be used uninitialized in this function [-Wmaybe-uninitialized]
  while(!isdigit(ch) && ch!='-'){
         ~~~~~~~^~~~
/in/foo.cc:45:7: note: 'ch' was declared here
  char ch;
       ^~