foo.cc: In function 'int isLeapYear(int)':
foo.cc:8:18: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
    8 |  return year%4==0&&year%100!=0||year%400==0;
      |         ~~~~~~~~~^~~~~~~~~~~~~
foo.cc: In function 'int pastDays(int, int, int)':
foo.cc:30:1: warning: no return statement in function returning non-void [-Wreturn-type]
   30 | }
      | ^
foo.cc: In function 'int main()':
foo.cc:33:21: warning: unused variable 'i' [-Wunused-variable]
   33 |  int year,month,day,i,a,sum=0;
      |                     ^
foo.cc:33:23: warning: unused variable 'a' [-Wunused-variable]
   33 |  int year,month,day,i,a,sum=0;
      |                       ^
foo.cc:33:25: warning: unused variable 'sum' [-Wunused-variable]
   33 |  int year,month,day,i,a,sum=0;
      |                         ^~~

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