/in/foo.cc: In function 'int main()':
/in/foo.cc:6:10: warning: statement has no effect [-Wunused-value]
    6 |         P<=10;
      |         ~^~~~
/in/foo.cc:8:13: warning: comparison of constant '20' with boolean expression is always true [-Wbool-compare]
    8 |         10<P<=20;
      |         ~~~~^~~~
/in/foo.cc:8:11: warning: comparisons like 'X<=Y<=Z' do not have their mathematical meaning [-Wparentheses]
    8 |         10<P<=20;
      |         ~~^~
/in/foo.cc:8:13: warning: statement has no effect [-Wunused-value]
    8 |         10<P<=20;
      |         ~~~~^~~~
/in/foo.cc:10:6: warning: statement has no effect [-Wunused-value]
   10 |     P>20;
      |     ~^~~
/in/foo.cc:5:13: warning: unused variable 'T' [-Wunused-variable]
    5 |         int T,P,Ro,L;
      |             ^
/in/foo.cc:7:10: warning: 'Ro' is used uninitialized [-Wuninitialized]
    7 |         P=Ro;
      |         ~^~~
/in/foo.cc:5:17: note: 'Ro' was declared here
    5 |         int T,P,Ro,L;
      |                 ^~
/in/foo.cc:9:10: warning: 'L' is used uninitialized [-Wuninitialized]
    9 |         P=L;
      |         ~^~
/in/foo.cc:5:20: note: 'L' was declared here
    5 |         int T,P,Ro,L;
      |                    ^