This repo contains the code for Bank Management System written in C. This program will create and maintain a Bank management system to keep track of Accounts inside the bank. Each Account has an account number, name, mobile, email address, balance, and date opened(another struct of month and year). We have written this code following naming conventions and clean code concepts to make the code work in an optimized and efficient way. Many approaches have been followed to apply optimization techniques to reduce memory consumption and decrease the time complexity. We also put into consideration the security standards that may keep our program immune to cyberthreats and vulnerabilities.
Throughout this section you’ll get a clear overview over the implementation of the functions in this program. Before we start diving into the program let’s get a general overview on the data and database. The data of the users and accounts is saved within a text file containing the data cells with a comma separating each cell.
First step of our program is logging in for the employees stored within the file users.txt. The program creates an array of structs for users with a password and username. The function readUser() is called to open the file and read the data stored in it and store it in the array of stucts of users.
After then, the login() function takes place by checking the entered username and password matches the ones stored in the database.
After a successful login the program calls loadAccounts() which should start loading the data of the accounts stored inside the accounts.txt file. By applying this method we can ensure that the data wont be retrieved if the user is not authorized which applies the concept of least privilege. The function stores the data in an array of structs of type Account. Main algorithm goes by reading a line from the file then passeing this line to strtok() which separates the line according to the comma delimiter. Each time the initial token starts a series of tests is done to assign all the strcut attributes until the token equal NULL. Everytime the function fgets() reads a line it adds one to the acCounts which is a global variable that holds number of accounts.
After loading the data of the accounts stored in the database we move to the actual program. The program calls Menu() function which is the main routine of the program. It contains a while loop that holds the whole program options within.
It asks the user to enter the option desired then the user is required to enter the name of the option as shown on the screen. The menu acts as a CLI it takes a string and converts it to upper case using StrToUpper() function which makes all the string characters in upper case.
We chose this approach to make the program not case sensitive so the user is able to enter the option in any case they want.
According to the chosen operation the function calls the operation function then after the function ends and is popped off from the stack it returns to the while loop of the Menu().
So the first operation we got is the Add() which adds a user to the database. The function asks the user to enter a valid account number and it keeps asking the user until they enter an account number that doesn’t exist in the database and is valid. A valid account number is checked by checkAccountNo() which returns 1 if valid ;otherwise, it returns 0. A vild account number means it has a length of 10-digits and doesn’t contain any letters or special characters. The existence check is done using AccountExistenceCheck() which returns 0 if it exists by looping through all the account numbers stored in the array of structs. After a valid account number is entered the mobile number is required. Checking on the mobile number is done using checkNumber() which returns 1 if valid. A valid mobile number contains 11-digits without any characters. After entering all valid data function asks you if you want to save ,you can either choose yes or no. After that, You;re asked if you want to add more accounts without returning to main. After adding the account the accounts counter increases by one and the data entered is assigned to the object located in the array of structs. You have to notice that when a new account is added its balance is set to 0.0 by default. The function sets the date of the account opened as the current date using the time() function which returns time in seconds since 1970 and then the output is formalized using the function locate().
This operation gives the user the privilege to delete an account but this account must have zero balance. The ideo of the function Delete() is locating the account number to be deleted after it checks it for validity, existence, and balance. After locating the account by using locateAccount() function it swaps the struct saved in this index in the array of structs with the next account until it makes it at the end of the accounts in the array. After then, It decrements the acCount which holds the number of accounts. So the next account to be added will overwrite the data of that account to be deleted and even if there wasn’t an account to be added the function Save() will save all the account except it.
Our program supports modifying your data by calling Modify() function but only the User name, Mobile number and email address. It has the same scenario as Add(), checks account number then gives you the options to modify the desired data. The function calls loadAccIndex() function which returns the index of the given account number. You can save the new data by typing Y or y when you’re asked. You have the ability to modify other accounts without returning to main.
Let’s get more Financial! You can transfer an amount of money not exceeding 10000$ per transaction by calling the function Transfer(). This function asks you to enter the sender and receiver account numbers and performs validation and existence checks. It asks you to enter the amount of money to be transferred which has to be numbers only and smaller than or equal your balance. It uses also the function loadAccIndex() to locate the two accounts, add the amount to reciever balance and subtract it from sender balance. After the transaction it asks you whether you want to save or not same as mentioned before. Whenever you do any transaction a file with the account number as its name is created as a history log for your operations. You can transfer money again without returning back to the main.
Same as Transfer() but it calls Deposit() function which takes one account number. It has the same restrictions as transfer in terms of max amount per transaction. You can save or not as the rest and repeat the operation if you want to. Remember that a file with its name same as the account number is created containig the history of your transactions.
Same as Deposit() but it calls Withdraw() function which takes one account number. It has the same restrictions as transfer in terms of max amount per transaction. You can save or not as the rest and repeat the operation if you want to. Remember that a file with its name same as the account number is created containig the history of your transactions.
This operation calls Query() Which asks you for an account number then checks its validity. It searches in the database using loadAccIndex() for this account number then calls function printUser() which prints all the information about a specific user. You can perform the same operation again without returning to main as the rest of operations.
This function enables the user to search in the database of user names with any keyword then it prints all the users with matching pattern of strings. It uses strstr() function to do this job of searching for the pattern given as keyword inside the strings of the usernames. It converts the keyword into upper case using StrToUpper() function and does the same with usernames in the array of structs so that it can handle case sensitivity. After it finds the matching results it calls the funct printUser() to print all users with matching results. You can repeat the process like the rest for sure.
This function is the User Joker card. The function Sort() prints out all the accounts in the database in sorted way according to two factors. The first factor is wheter you want sortByName() or sortByBalance or sortBydate() and the second factor is whether you want it to be printed in ascending or descending order. We used the Bubble sort algorithm in the thress methods of sorting. For example, the sortByName() uses strcmp() to compare the user names saved and swap them according to order chosen. The same goes with sortByBalance() and SortByDate(). When sorting by date we compare the years first then we compare months. After swapping the indices of the elements we assign these indices in a temporary array so that we can loop through this array of indices and use printUser() to print the users in the order of indecies are sorted. The temporary array is created using the function fillArray() which reserves a place in the memory using malloc() and fills it with numbers from 0 to acCount -1.
By calling Report() function it opens the text file of an entered and checked account number from the user then it prints out the last 5 transactions stored in the file named by account number. It counts number of lines of the file of history then subtracts 5 from it to start from the last five lines then it calls the function fseek() to return to the start of the file to count from the beginning. You can repeat this operation too.
Holds the user manual data and prints it on screen to help the user on how to deal with the program. It includes all the operations allowed for users and restrictions of input data.
We have mentioned the function Save() nearly in all the operations that can change data in the database. This function takes out all the data stored with the array of strcuts and print it in the same order of cells as it was retrieved at the beginning of the program. It uses fprintf() and fopen() to open the accounts.txt file