/in/foo.c: In function 'main':
/in/foo.c:10:27: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  if(year%400==0||year%4==0&&year%100!=0)
                  ~~~~~~~~~^~~~~~~~~~~~~
/in/foo.c:36:21: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  if(a%400==0||a%4==0&&a%100!=0)
               ~~~~~~^~~~~~~~~~
/in/foo.c:71:23: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
    if(i%400==0||i%4==0&&i%100!=0)
                 ~~~~~~^~~~~~~~~~
/in/foo.c:4:30: warning: unused variable 'j' [-Wunused-variable]
 {   int a,b,c,year,month,d,i,j,m,sum,flag,day,s=0,s1=0;
                              ^