HW13.3

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <conio.h>

#define MAXSIZE 1000

int checkValidNumber (char s[]) {
    char format[] = "DD-LDDDD.DD";
    int i;
    if (strlen(s) != strlen(format))
        return 0;
    for (i = 0; i < strlen(s); ++i) {
        if ((format[i] == 'D' && isdigit(s[i]))
            || (format[i] == 'L' && isalpha(s[i]))
            || (format[i] != 'L' && (s[i] == format[i]))) {
            if (i == 1) {
                if ((s[i-1] >= '2' || s[i-1] <= '3') && (s[i] <= '2' || s[i] >= '9')) {}
                else
                    return 0;
            }
        } else
            return 0;
    }
    return 1;
}

int main () {
    char numberPlate[MAXSIZE];
    while (1) {
        printf("Enter the number plate: ");
        scanf("%s", numberPlate);
        if (checkValidNumber(numberPlate)) {
            printf("\n!!! Valid number plate !!!\n\n");
        } else {
            printf("\n!!! Invalid number plate !!!\n\n");
        }
    }
    getch();
    return 0;
}