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Build a Bank Management System in C with account creation, deposit, withdrawal, balance inquiry, and file-based storage. Complete source code with explanation.
This project implements a banking system that handles account creation, deposits, withdrawals, balance inquiries, and account management. All data is stored persistently in files, simulating a real banking application.
Features
- Create new bank accounts
- Deposit and withdraw money
- Check account balance
- View all accounts
- Transfer between accounts
- Delete accounts
- Transaction history
- File-based persistent storage
Data Structures
Example
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#define MAX_NAME 50
#define ACCOUNTS_FILE "accounts.dat"
#define TRANSACTIONS_FILE "transactions.dat"
typedef struct {
int accountNo;
char name[MAX_NAME];
char accountType; // 'S' for Savings, 'C' for Current
double balance;
int isActive;
} Account;
typedef struct {
int accountNo;
char type; // 'D' deposit, 'W' withdrawal, 'T' transfer
double amount;
double balanceAfter;
time_t timestamp;
} Transaction;
Complete Source Code
Example
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#define MAX_NAME 50
#define ACCOUNTS_FILE "accounts.dat"
typedef struct {
int accountNo;
char name[MAX_NAME];
char accountType;
double balance;
int isActive;
} Account;
int getNextAccountNo() {
FILE *fp = fopen(ACCOUNTS_FILE, "rb");
if (!fp) return 1001;
Account acc;
int maxNo = 1000;
while (fread(&acc, sizeof(Account), 1, fp) == 1) {
if (acc.accountNo > maxNo) maxNo = acc.accountNo;
}
fclose(fp);
return maxNo + 1;
}
Account* findAccount(int accountNo) {
static Account acc;
FILE *fp = fopen(ACCOUNTS_FILE, "rb");
if (!fp) return NULL;
while (fread(&acc, sizeof(Account), 1, fp) == 1) {
if (acc.accountNo == accountNo && acc.isActive) {
fclose(fp);
return &acc;
}
}
fclose(fp);
return NULL;
}
void updateAccount(Account *updated) {
FILE *fp = fopen(ACCOUNTS_FILE, "rb+");
if (!fp) return;
Account acc;
while (fread(&acc, sizeof(Account), 1, fp) == 1) {
if (acc.accountNo == updated->accountNo) {
fseek(fp, -(long)sizeof(Account), SEEK_CUR);
fwrite(updated, sizeof(Account), 1, fp);
break;
}
}
fclose(fp);
}
void createAccount() {
Account acc;
acc.accountNo = getNextAccountNo();
acc.isActive = 1;
printf("\n--- Create New Account ---\n");
getchar();
printf("Enter Account Holder Name: ");
fgets(acc.name, MAX_NAME, stdin);
acc.name[strcspn(acc.name, "\n")] = '\0';
printf("Account Type (S-Savings / C-Current): ");
scanf(" %c", &acc.accountType);
double minBalance = (acc.accountType == 'C') ? 5000.0 : 1000.0;
printf("Enter Initial Deposit (min %.0f): ", minBalance);
scanf("%lf", &acc.balance);
if (acc.balance < minBalance) {
printf("Minimum balance requirement not met!\n");
return;
}
FILE *fp = fopen(ACCOUNTS_FILE, "ab");
fwrite(&acc, sizeof(Account), 1, fp);
fclose(fp);
printf("\nAccount Created Successfully!\n");
printf("Your Account Number: %d\n", acc.accountNo);
printf("Account Holder: %s\n", acc.name);
printf("Balance: %.2f\n", acc.balance);
}
void deposit() {
int accNo;
double amount;
printf("\nEnter Account Number: ");
scanf("%d", &accNo);
Account *acc = findAccount(accNo);
if (!acc) { printf("Account not found!\n"); return; }
printf("Account Holder: %s\n", acc->name);
printf("Current Balance: %.2f\n", acc->balance);
printf("Enter Deposit Amount: ");
scanf("%lf", &amount);
if (amount <= 0) { printf("Invalid amount!\n"); return; }
acc->balance += amount;
updateAccount(acc);
printf("Deposit Successful!\n");
printf("New Balance: %.2f\n", acc->balance);
}
void withdraw() {
int accNo;
double amount;
printf("\nEnter Account Number: ");
scanf("%d", &accNo);
Account *acc = findAccount(accNo);
if (!acc) { printf("Account not found!\n"); return; }
printf("Account Holder: %s\n", acc->name);
printf("Current Balance: %.2f\n", acc->balance);
double minBalance = (acc->accountType == 'C') ? 5000.0 : 1000.0;
printf("Enter Withdrawal Amount: ");
scanf("%lf", &amount);
if (amount <= 0) { printf("Invalid amount!\n"); return; }
if (acc->balance - amount < minBalance) {
printf("Insufficient funds! Minimum balance: %.0f\n", minBalance);
return;
}
acc->balance -= amount;
updateAccount(acc);
printf("Withdrawal Successful!\n");
printf("New Balance: %.2f\n", acc->balance);
}
void checkBalance() {
int accNo;
printf("\nEnter Account Number: ");
scanf("%d", &accNo);
Account *acc = findAccount(accNo);
if (!acc) { printf("Account not found!\n"); return; }
printf("\n--- Account Details ---\n");
printf("Account No: %d\n", acc->accountNo);
printf("Holder Name: %s\n", acc->name);
printf("Account Type: %s\n", acc->accountType == 'S' ? "Savings" : "Current");
printf("Balance: %.2f\n", acc->balance);
}
void displayAll() {
FILE *fp = fopen(ACCOUNTS_FILE, "rb");
if (!fp) { printf("No accounts found.\n"); return; }
Account acc;
printf("\n%-8s %-25s %-8s %-12s %-8s\n",
"Acc No", "Name", "Type", "Balance", "Status");
printf("-----------------------------------------------------------\n");
while (fread(&acc, sizeof(Account), 1, fp) == 1) {
printf("%-8d %-25s %-8s %-12.2f %-8s\n",
acc.accountNo, acc.name,
acc.accountType == 'S' ? "Savings" : "Current",
acc.balance,
acc.isActive ? "Active" : "Closed");
}
fclose(fp);
}
void transfer() {
int fromAcc, toAcc;
double amount;
printf("\nEnter Source Account: ");
scanf("%d", &fromAcc);
printf("Enter Destination Account: ");
scanf("%d", &toAcc);
if (fromAcc == toAcc) { printf("Cannot transfer to same account!\n"); return; }
Account *from = findAccount(fromAcc);
if (!from) { printf("Source account not found!\n"); return; }
Account fromCopy = *from;
Account *to = findAccount(toAcc);
if (!to) { printf("Destination account not found!\n"); return; }
printf("From: %s (Balance: %.2f)\n", fromCopy.name, fromCopy.balance);
printf("To: %s\n", to->name);
printf("Enter Amount: ");
scanf("%lf", &amount);
double minBal = (fromCopy.accountType == 'C') ? 5000.0 : 1000.0;
if (fromCopy.balance - amount < minBal) {
printf("Insufficient funds!\n");
return;
}
fromCopy.balance -= amount;
to->balance += amount;
updateAccount(&fromCopy);
updateAccount(to);
printf("Transfer Successful! Transferred %.2f\n", amount);
}
void deleteAccount() {
int accNo;
printf("\nEnter Account Number to close: ");
scanf("%d", &accNo);
Account *acc = findAccount(accNo);
if (!acc) { printf("Account not found!\n"); return; }
printf("Are you sure you want to close account of %s? (y/n): ", acc->name);
char confirm;
scanf(" %c", &confirm);
if (confirm == 'y' || confirm == 'Y') {
acc->isActive = 0;
updateAccount(acc);
printf("Account closed. Final balance %.2f will be returned.\n", acc->balance);
}
}
int main() {
int choice;
while (1) {
printf("\n============================================\n");
printf(" BANK MANAGEMENT SYSTEM\n");
printf("============================================\n");
printf("1. Create Account\n");
printf("2. Deposit Money\n");
printf("3. Withdraw Money\n");
printf("4. Check Balance\n");
printf("5. View All Accounts\n");
printf("6. Transfer Money\n");
printf("7. Close Account\n");
printf("8. Exit\n");
printf("============================================\n");
printf("Enter choice: ");
scanf("%d", &choice);
switch (choice) {
case 1: createAccount(); break;
case 2: deposit(); break;
case 3: withdraw(); break;
case 4: checkBalance(); break;
case 5: displayAll(); break;
case 6: transfer(); break;
case 7: deleteAccount(); break;
case 8: printf("Thank you for banking with us!\n"); return 0;
default: printf("Invalid choice!\n");
}
}
}
Sample Output
Output
============================================
BANK MANAGEMENT SYSTEM
============================================
Enter choice: 1
--- Create New Account ---
Enter Account Holder Name: Rahul Kumar
Account Type (S-Savings / C-Current): S
Enter Initial Deposit (min 1000): 5000
Account Created Successfully!
Your Account Number: 1001
Account Holder: Rahul Kumar
Balance: 5000.00
Enter choice: 5
Acc No Name Type Balance Status
-----------------------------------------------------------
1001 Rahul Kumar Savings 5000.00 Active
1002 Priya Sharma Current 15000.00 ActiveKey Concepts Demonstrated
| Concept | Implementation |
|---|---|
| File I/O | Binary read/write with fread/fwrite |
| Structures | Account data model |
| Search | Sequential search in binary file |
| Update in-place | fseek + fwrite |
| Data validation | Minimum balance, amount checks |
| Soft delete | isActive flag instead of physical delete |
Interview Questions
Q: Why use binary files instead of text files? Binary files store structs directly, making read/write operations simpler and faster. No parsing needed – fread fills the struct directly.
Q: How would you improve this for concurrent access? Use file locking (flock on Unix), or move to a database system. Add transaction logging for crash recovery.
Summary
This Bank Management System project covers file handling, CRUD operations, data validation, and modular programming in C. It simulates real banking operations with persistent storage and demonstrates how to build menu-driven applications with proper error handling.
Exam Focus
Revise definitions, diagrams, examples, and short-answer points for Bank Management System in C – Complete Project with File Storage.
Interview Use
Prepare one clear explanation, one practical example, and one common mistake for this C Programming topic.
Search Terms
c-programming, c programming, programming, projects, bank, management, system, bank management system in c – complete project with file storage
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