foo.cc: In function 'int main()':
foo.cc:16:26: warning: comparison of constant '10' with boolean expression is always true [-Wbool-compare]
             else if (1<=x<10)
                      ~~~~^~~
foo.cc:16:23: warning: comparisons like 'X<=Y<=Z' do not have their mathematical meaning [-Wparentheses]
             else if (1<=x<10)
                      ~^~~
foo.cc:19:27: warning: comparison of constant '15' with boolean expression is always true [-Wbool-compare]
             else if (10<=x<15)
                      ~~~~~^~~
foo.cc:19:24: warning: comparisons like 'X<=Y<=Z' do not have their mathematical meaning [-Wparentheses]
             else if (10<=x<15)
                      ~~^~~
foo.cc:22:27: warning: comparison of constant '30' with boolean expression is always true [-Wbool-compare]
             else if (15<=x<30)
                      ~~~~~^~~
foo.cc:22:24: warning: comparisons like 'X<=Y<=Z' do not have their mathematical meaning [-Wparentheses]
             else if (15<=x<30)
                      ~~^~~

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