5.5

#include<stdio.h>  int main()  {      int year,flag;      printf("Enter year:");      scanf("%d",&year);      if(year%4==0&&year%100!=0||year%400==0)          flag=1;      else          flag=0;      if(flag==1)          printf("%d is a leap year!\n",year);      else          printf("%d is not a leap year\n",year);      return 0;  }