/in/foo.cc: In function 'int main()':
/in/foo.cc:8:10: warning: comparison of constant '100' with boolean expression is always true [-Wbool-compare]
  if (1<=x<=100)
      ~~~~^~~~~
/in/foo.cc:8:7: warning: comparisons like 'X<=Y<=Z' do not have their mathematical meaning [-Wparentheses]
  if (1<=x<=100)
      ~^~~