/in/foo.cc: In function 'int main()':
/in/foo.cc:12:17: warning: init-statement in selection statements only available with '-std=c++17' or '-std=gnu++17' [-Wc++17-extensions]
   12 |         else if(cv!='+'&&cv!='-'&&cv!='/'&&cv!='*';
      |                 ^~
/in/foo.cc:12:42: warning: statement has no effect [-Wunused-value]
   12 |         else if(cv!='+'&&cv!='-'&&cv!='/'&&cv!='*';
      |                 ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~
/in/foo.cc:13:41: error: expected ')' before ';' token
   13 |                cout<<"Invalid operator!";
      |                                         ^
      |                                         )
/in/foo.cc:12:16: note: to match this '('
   12 |         else if(cv!='+'&&cv!='-'&&cv!='/'&&cv!='*';
      |                ^