/in/foo.cc: In function 'int main()':
/in/foo.cc:7:5: warning: comparison of constant '100' with boolean expression is always true [-Wbool-compare]
  1<x<100;
  ~~~^~~~
/in/foo.cc:7:3: warning: comparisons like 'X<=Y<=Z' do not have their mathematical meaning [-Wparentheses]
  1<x<100;
  ~^~
/in/foo.cc:7:5: warning: statement has no effect [-Wunused-value]
  1<x<100;
  ~~~^~~~