foo.cc: In function 'int guo(int, int, int)':
foo.cc:24:26: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   24 |    if(a%400==0 || a%4==0 && a%100!=0)
      |                   ~~~~~~~^~~~~~~~~~~
foo.cc: In function 'int run(int)':
foo.cc:40:24: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   40 |  if(a%400==0 || a%4==0 && a%100!=0)
      |                 ~~~~~~~^~~~~~~~~~~
foo.cc: In function 'int yuetian(int, int)':
foo.cc:59:25: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   59 |   if(a%400==0 || a%4==0 && a%100!=0)
      |                  ~~~~~~~^~~~~~~~~~~
foo.cc:68:1: warning: control reaches end of non-void function [-Wreturn-type]
   68 | }
      | ^

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