UTS ALGO NO 2

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

int main(void) {
    int max_user;
    char cardinal[10][10] = {"1st", "2nd", "3rd", "4th", "5th", "6th", "7th", "8th", "9th", "10th"};
    char username[10][50];
    char* temp;
    char password[10][50];
    char newpassword[10][50];
    char email[10][50];
    char *p;

    do { //Maximum users
        printf("Input max user (3-10) : "); scanf("%d", &max_user); fflush(stdin);

    }while (max_user > 10 || max_user < 3);

    bool unique;


    for (int i = 0; i < max_user; i++) {

        do {
            unique = true; //Check if the username inputted has been inputted before
            printf("Input the %s username : ", cardinal[i]); scanf("%s", &username[i]); fflush(stdin);
            if(i!=0) {
                for (int a = 0; a < i; a++) {
                    if(strcmp(username[i], username[a]) == 0) {
                        unique = false;
                        break;
                    }
                }
            }
        }while(unique == false);

        do { //Password needs to be at least 5 characters
            printf("Input Password (Min 5 characters) : ");
            scanf("%s", &password[i]); fflush(stdin);

        }while(strlen(password[i]) < 5);

        printf("\nPassword converted ...\n");
        int n = strlen(password[i]);

        for (int a = 0; a < n; a++) {
            if (a == 0) { //First and last character are changed into upper case
                password[i][a] = toupper(password[i][a]);
            }else if(a == n-1) {
                password[i][a] = toupper(password[i][a]);
            }else { //Other characters are changed into lower case
                password[i][a] = tolower(password[i][a]);
            }

            switch(password[i][a]) { //Changing password
            case 'O' :
                password[i][a] = '0'; break;
            case 'o' :
                password[i][a] = '0'; break;
            case 'I' :
                password[i][a] = '1'; break;
            case 'i' :
                password[i][a] = '1'; break;
            case 'S' :
                password[i][a] = '$'; break;
            case 's' :
                password[i][a] = '$'; break;
            case 'T' :
                password[i][a] = '7'; break;
            case 't' :
                password[i][a] = '7';

            }


        }

        strcat(password[i], "!"); //Adding a "!" to password array

        //By now, password array has fundamentally changed, so program will ask user to
        // input new password, which will be compared to password array

        printf("New password is %s\n\n", password[i]);
        do {
            printf("Now please enter your new password : ");
            scanf("%s", newpassword[i]); fflush(stdin);
        }while(strcmpi(newpassword[i], password[i]) != 0);

        bool pass;
        do {
            pass = false; //Initializing boolean value of pass
            printf("Nice! Please enter your email : ");
            scanf("%s", email[i]); fflush(stdin);

            int x = strlen(email[i]);
            char* p = &email[i][(x - 10)];
            //The output of strstr is a pointer, so we initialize value of p as
            // "the adress" of email[i][x - 10]. 10 Because @gmail.com as well as
            // @yahoo.com contains 10 character

            if (p == strstr(email[i], "@gmail.com") || p == strstr(email[i], "@yahoo.com")) {
                //Here you can see we compare p to strstr, and if inputted email successfully
                //goes through this selection, then boolean value of pass becomes true
                //These all will be done again and again if inputted email fails to go through
                //this selection
                pass = true;
            }


        }while (pass == false);

        system("cls");
    }

    printf("%-10s %-20s\n\n", "Name", "Email");
    for(int i = 0 ; i < max_user; i++) {
        printf("%-10s %-20s\n", username[i], email[i]);
    }
    printf("Thank you for using this program ");


    getchar();
}