C Program to Display the ATM Transaction

/*
 * C Program to Display the ATM Transaction
 */
#include <stdio.h>
 
unsigned long amount=1000, deposit, withdraw;
int choice, pin, k;
char transaction ='y';
 
void main()
{
    while (pin != 1520)
    {
        printf("ENTER YOUR SECRET PIN NUMBER:");
        scanf("%d", &pin);
        if (pin != 1520)
        printf("PLEASE ENTER VALID PASSWORD\n");
    }
    do
    {
        printf("********Welcome to ATM Service**************\n");
        printf("1. Check Balance\n");
        printf("2. Withdraw Cash\n");
        printf("3. Deposit Cash\n");
        printf("4. Quit\n");
        printf("******************?**************************?*\n\n");
        printf("Enter your choice: ");
        scanf("%d", &choice);
        switch (choice)
        {
        case 1:
            printf("\n YOUR BALANCE IN Rs : %lu ", amount);
            break;
        case 2:
            printf("\n ENTER THE AMOUNT TO WITHDRAW: ");
            scanf("%lu", &withdraw);
            if (withdraw % 100 != 0)
            {
                printf("\n PLEASE ENTER THE AMOUNT IN MULTIPLES OF 100");
            }
            else if (withdraw >(amount - 500))
            {
                printf("\n INSUFFICENT BALANCE");
            }
            else
            {
                amount = amount - withdraw;
                printf("\n\n PLEASE COLLECT CASH");
                printf("\n YOUR CURRENT BALANCE IS%lu", amount);
            }
            break;
        case 3:
            printf("\n ENTER THE AMOUNT TO DEPOSIT");
            scanf("%lu", &deposit);
                        amount = amount + deposit;
            printf("YOUR BALANCE IS %lu", amount);
            break;
        case 4:
            printf("\n THANK U USING ATM");
            break;
        default:
            printf("\n INVALID CHOICE");
        }
        printf("\n\n\n DO U WISH TO HAVE ANOTHER TRANSCATION?(y/n): \n");
        fflush(stdin);
        scanf("%c", &transaction);
        if (transaction == 'n'|| transaction == 'N')
                    k = 1;
    } while (!k);
    printf("\n\n THANKS FOR USING OUT ATM SERVICE");
}

Output

ENTER YOUR SECRET PIN NUMBER:1520
********Welcome to ATM Service**************
1. Check Balance
2. Withdraw Cash
3. Deposit Cash
4. Quit
******************?**************************?*
 
Enter your choice: 1
 
YOUR BALANCE IN Rs : 1000
 
 
DO U WISH TO HAVE ANOTHER TRANSCATION?(y/n):
********Welcome to ATM Service**************
1. Check Balance
2. Withdraw Cash
3. Deposit Cash
4. Quit
******************?**************************?*
 
Enter your choice: 2
 
ENTER THE AMOUNT TO WITHDRAW: 200
 
 
PLEASE COLLECT CASH
YOUR CURRENT BALANCE IS 800
 
DO U WISH TO HAVE ANOTHER TRANSCATION?(y/n):
********Welcome to ATM Service**************
1. Check Balance
2. Withdraw Cash
3. Deposit Cash
4. Quit
******************?**************************?*
 
Enter your choice: 3
 
ENTER THE AMOUNT TO DEPOSIT 5000
YOUR BALANCE IS 5800
 
 
DO U WISH TO HAVE ANOTHER TRANSCATION?(y/n):
********Welcome to ATM Service**************
1. Check Balance
2. Withdraw Cash
3. Deposit Cash
4. Quit
******************?**************************?*
 
Enter your choice: 1
 
YOUR BALANCE IN Rs : 5800
 
 
DO U WISH TO HAVE ANOTHER TRANSCATION?(y/n):
********Welcome to ATM Service**************
1. Check Balance
2. Withdraw Cash
3. Deposit Cash
4. Quit
******************?**************************?*
 
Enter your choice: 4
 
THANK U USING ATM
 
 
DO U WISH TO HAVE ANOTHER TRANSCATION?(y/n):
********Welcome to ATM Service**************
1. Check Balance
2. Withdraw Cash
3. Deposit Cash
4. Quit
******************?**************************?*
 
Enter your choice: 4
 
THANK U USING ATM
 
 
DO U WISH TO HAVE ANOTHER TRANSCATION?(y/n):
********Welcome to ATM Service**************
1. Check Balance
2. Withdraw Cash
3. Deposit Cash
4. Quit
******************?**************************?*
 
Enter your choice: n
 
THANK U USING ATM
 
 
DO U WISH TO HAVE ANOTHER TRANSCATION?(y/n):
 
THANKS FOR USING OUT ATM SERVICE.