pvjc20/du3/program.c

#include <stdio.h>

int main(){
    int day;
    int month;
    int year;
    scanf("%d.%d.%d", &day, &month, &year);
    if(day < 1 || day > 31 || month < 1 || month > 12){
        puts("Neplatny datum");
        return 0;
    }
    if(month == 2 && day > 29){
        puts("Neplatny datum");
        return 0;
    }
    if(year % 4 != 0 && month == 2 && day > 28){
        puts("Neplatny datum");
        return 0;
    }
    if(month == 4 || month == 6 || month == 9 || month == 11 && day > 30){
        puts("Neplatny datum");
        return 0;
    }

    day += 7;
    if(year % 4 != 0 && month == 2 && day > 28){
        month++;
        day -= 28;
    }
    else if(month == 2 && day > 29){
        month++;
        day -= 29;
    }
    else if(month == 4 && month == 6 && month == 9 && month == 11 && day > 30){
        month++;
        day -= 30;
    }
    else if(day > 31){
        month++;
        day -= 31;
    }
    if(month == 13){
        month = 1;
        year++;
    }

    else if(month < 10){
        printf("%d.0%d.%d\n", day, month, year);
    }
    else{
        printf("%d.%d.%d\n", day, month, year);
    }
}