/in/foo.cc: In function 'std::__cxx11::string who_is_win(std::__cxx11::string, std::__cxx11::string)':
/in/foo.cc:7:14: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  if(a[0]=='R'&&b[0]=='S' || a[0]=='P'&&b[0]=='R' || a[0]=='S'&&b[0]=='P')
               
/in/foo.cc:7:62: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  if(a[0]=='R'&&b[0]=='S' || a[0]=='P'&&b[0]=='R' || a[0]=='S'&&b[0]=='P')
                                                               
/in/foo.cc:9:19: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  else if(a[0]=='S'&&b[0]=='R' || a[0]=='R'&&b[0]=='P' || a[0]=='P'&&b[0]=='S')
                    
/in/foo.cc:9:67: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  else if(a[0]=='S'&&b[0]=='R' || a[0]=='R'&&b[0]=='P' || a[0]=='P'&&b[0]=='S')
                                                                    
/in/foo.cc:11:20: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   else if(a[0]=='R'&&b[0]=='R' || a[0]=='S'&&b[0]=='S' || a[0]=='P'&&b[0]=='P')
                     
/in/foo.cc:11:68: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   else if(a[0]=='R'&&b[0]=='R' || a[0]=='S'&&b[0]=='S' || a[0]=='P'&&b[0]=='P')
                                                                     
/in/foo.cc:13:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^