/in/foo.cc: In function 'int main()':
/in/foo.cc:7:15: warning: comparison of constant '999' with boolean expression is always true [-Wbool-compare]
    7 |         100<=s<=999;
      |         ~~~~~~^~~~~
/in/foo.cc:7:12: warning: comparisons like 'X<=Y<=Z' do not have their mathematical meaning [-Wparentheses]
    7 |         100<=s<=999;
      |         ~~~^~~
/in/foo.cc:7:15: warning: statement has no effect [-Wunused-value]
    7 |         100<=s<=999;
      |         ~~~~~~^~~~~