/in/foo.cc: In function 'int main()':
/in/foo.cc:12:13: warning: 'c' is used uninitialized in this function [-Wuninitialized]
  for(; c>'9'||c<'0'; c=getchar())if(c=='-')flag=false;
        ~~~~~^~~~~~~
/in/foo.cc:10:7: note: 'c' was declared here
  char c;
       ^
/in/foo.cc:12:13: warning: 'c' may be used uninitialized in this function [-Wmaybe-uninitialized]
  for(; c>'9'||c<'0'; c=getchar())if(c=='-')flag=false;
        ~~~~~^~~~~~~
/in/foo.cc:10:7: note: 'c' was declared here
  char c;
       ^
/in/foo.cc:12:13: warning: 'c' may be used uninitialized in this function [-Wmaybe-uninitialized]
  for(; c>'9'||c<'0'; c=getchar())if(c=='-')flag=false;
        ~~~~~^~~~~~~
/in/foo.cc:10:7: note: 'c' was declared here
  char c;
       ^