atm file processing

Hello all,

can anyone PLEASE help me regarding my problem, I have to write an atm machine program in c and I have to use file processing.
How can I make a file where is stored everything I do on that atm program, like if I entered to check balance, in file should be written balance: 8500, for withdraw: withdraw: 100,balance: 8400, for deposit, deposit: 400, balance 8800.

thank you.

here is the code:

Code:

---

#include<stdio.h>
#include<stdlib.h>
int main()
{


  int pin;
  int i;
  int almeidPin={1234};
  int hadisPin={2345};
  int almirPin={3456};
  int ahmedPin={4567};
  int almaPin={5678};
  int lejlaPin={6789};
  int selmaPin={7890};
  int belmaPin={1010};
  int newTry;
  int menuOption;
  int firstWthd;
  double balance = 8500;
  double deposit;
  int withdraw;
  int cont;
  int option=0;


    printf("*****| WELCOME to Unknown Bank! Thank you for banking |*****\n\n\n");


    printf("_________________________| Main Menu |________________________\n");
    printf("..............................................................\n\n");
    printf("1)Enter Pin #\n");
    printf("2)Exit\n\n");
    printf("..............................................................\n\n");
    scanf("%d", &option);
    if (option!=1 && option!=2)
    printf("\nInvalid input,try again!\n\n");


    if (option==1)
{
system ("cls");
printf("\n      Pin Number Verification\n");
printf("-----------------------------------\n\n");
printf("\n__________Enter your pin:__________\n\n");
scanf("%d",&pin);


if (pin==almeidPin || pin==hadisPin || pin==almirPin || pin==ahmedPin
    || pin==almaPin || pin==lejlaPin || pin==selmaPin || pin==belmaPin) goto next;


else
for (i=0;i<3;i++)
{
    if(i==2) return 0;
    printf("\nWrong pin number! Enter your pin correctly:\n\n");
    scanf("%d",&newTry);
    if(newTry==almeidPin || newTry==hadisPin || newTry==almirPin || newTry==ahmedPin
    || newTry==almaPin || newTry==lejlaPin || newTry==selmaPin || newTry==belmaPin) goto next;


}


        next:
            system ("cls");
            printf("              Transactions\n");
            printf("------------------------------------------\n");
            printf("1) Balance\n\n2) Withdraw\n\n3) Deposit\n\n4) Exit\n\n");
            printf("------------------------------------------\n");
            scanf("%d",&menuOption);


                        switch(menuOption)
{
        case 1:
                printf("\n______________Balance iquiry______________\n\n");
        printf("Your balance is: %lf KM\n\n",balance);
        printf("Press 5 to continue...\n\n");
        scanf("%d",&cont);
        if (cont=5)
        goto next;
                                break;
        case 2:
                printf("\n_________________Withdraw_________________\n\n");


                printf("Enter amount you want to withdraw:\n\n");
        printf("1) 10KM          4) 80KM \n2) 20KM          5) 100KM \n3) 50KM          6) Other \n7) Cancel\n\n");


                scanf("%d",&firstWthd);
                if (firstWthd==1)
                {
                  balance=balance-10;
        printf("\nYour withdraw is: 10 KM");
                printf("\n\nYour remaining balance is: %lf KM\n\n",balance);
                printf("Press 5 to continue...\n\n");
        scanf("%d",&cont);
        if (cont=5)
        goto next;
                }
                else if (firstWthd==2)
                {
        balance=balance-20;
                printf("\nYour withdraw is: 20 KM");
                printf("\n\nYour remaining balance is: %lf KM\n\n",balance);
                printf("Press 5 to continue...\n\n");
        scanf("%d",&cont);
        if (cont=5)
        goto next;
                }
                else if (firstWthd==3)
                {
                balance=balance-50;
                printf("\nYour withdraw is: 50 KM");
                printf("\n\nYour remaining balance is: %lf KM\n\n",balance);
                printf("Press 5 to continue...\n\n");
        scanf("%d",&cont);
        if (cont=5)
        goto next;
                }
                else if (firstWthd==4)
                {
                balance=balance-80;
                printf("\nYour withdraw is: 80 KM");
                printf("\n\nYour remaining balance is: %lf KM\n\n",balance);
                printf("Press 5 to continue...\n\n");
        scanf("%d",&cont);
        if (cont=5)
        goto next;
                }
                else if (firstWthd==5)
                {
                balance=balance-100;
                printf("\nYour withdraw is: 100 KM");
                printf("\n\nYour remaining balance is: %lf KM\n\n",balance);
                printf("Press 5 to continue...\n\n");
        scanf("%d",&cont);
        if (cont=5)
        goto next;
                }
        else if (firstWthd==7)
        {
                return 0;
        }
                else if (firstWthd==6)
                printf ("\nEnter amount you want to withdraw:\n\n");
                scanf("%d",&withdraw);
                if (balance>withdraw && withdraw>0 && withdraw%10==0)
                {
                balance=balance-withdraw;
                printf("\nYour withdraw is: %d KM",withdraw);
                printf("\n\nYour remaining balance is: %lf KM\n\n",balance);
                printf("Press 5 to continue...\n\n");
        scanf("%d",&cont);
        if (cont=5)
        goto next;
                }
                else
                {
                printf("\nYou have to enter rounded number between 0 and %lf to withdraw!\n\n",balance);
                system ("pause");
                goto next;
                }
                break;
        case 3:
                printf("\n_________________Deposit__________________\n\n");
                printf("Enter your deposit:\n\n");
        scanf("%lf",&deposit);


                balance = balance + deposit;
                printf("\nYou deposited: %lf KM",deposit);
                printf("\n\nYour new balance is: %lf KM\n\n",balance);
                printf("Press 5 to continue...\n\n");
        scanf("%d",&cont);
        if (cont=5)
        goto next;
                break;
        case 4:
                printf("\n________________Exit mode_________________\n\n");
                break;
        default:
                printf("\nThat is invalid option!!!\n\n");
                system ("pause");
                goto next;


                break;


}
}


return 0;


}

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I added [code][/code] tags, so people can read your code - you should learn to use them

Now the next things you should address are
1. indentation, which is pretty poor; see here -> SourceForge.net: Indentation - cpwiki

2. 'goto' abuse. Change it into a while loop.

Code:

---

if (pin==almeidPin || pin==hadisPin || pin==almirPin || pin==ahmedPin
    || pin==almaPin || pin==lejlaPin || pin==selmaPin || pin==belmaPin

---

You should be using a do-while so you don't have to use this twice. Also, it would help to make an array of PINs and a separate function, in case you ever wanted to add more:

Code:

---

/* you need to have these */
int PINs[] = {almeidPen, hadisPin, ....};
int numPINs = sizeof(PINs) / sizeof(PINs[0]);

/* put this when you're trying to get input */
do {
    scanf("%d", &pin);
} while (!valid_PIN(pin, PINs, numPINs));

/* and then, check with this function */
bool valid_PIN (int pin, int *array, int size)
{
    /* lol, write it yourself */
}

---

These kinds of changes should be applied to the entirety of your code.