#include <stdio.h> int main () { int dd, mm, yy; printf("Please enter the date dd/mm/yy:\n"); scanf("%d/%d/%d", &dd, &mm, &yy); int bissextile = yy % 400 == 0 || (yy % 4 == 0 && yy % 100 != 0); if (dd>31 || dd<1 || mm>12 || mm<1) printf("Invalid date.\n"); if((mm==2 && dd<30 && bissextile) || (mm==2 && dd<29 && bissextile==0)) printf("valid date.\n"); else if((mm==4 || mm==6 || mm==9 || mm==11)&& dd<31) printf("valid date.\n"); else if(dd<31 && mm!=2) printf("valid date.\n"); else printf("Invalid date.\n"); return 0; }