diff --git a/concurrency/Threading_In_CPlusPlus/4.mutex/an_example_of_bank_account.cpp b/concurrency/Threading_In_CPlusPlus/4.mutex/an_example_of_bank_account.cpp
new file mode 100644
index 0000000..866b761
--- /dev/null
+++ b/concurrency/Threading_In_CPlusPlus/4.mutex/an_example_of_bank_account.cpp
@@ -0,0 +1,66 @@
+#include <iostream>
+#include <thread>
+#include <mutex>
+#include <vector>
+
+using namespace std;
+
+class BankAccount {
+public:
+    BankAccount() : balance(0) {}
+
+   
+    void deposit(int amount) {
+        lock_guard<mutex> lock(mtx);  
+        balance += amount;
+    }
+
+
+    void withdraw(int amount) {
+        lock_guard<mutex> lock(mtx);  
+        if (balance >= amount) {
+            balance -= amount;
+        } else {
+            cout << "Not enough funds to withdraw " << amount << endl;
+        }
+    }
+
+
+    int get_balance() const {
+        return balance;
+    }
+
+private:
+    int balance;      
+    mutable mutex mtx;  
+};
+
+void deposit_to_account(BankAccount& account) {
+    for (int i = 0; i < 1000; ++i) {
+        account.deposit(1);  
+    }
+}
+
+void withdraw_from_account(BankAccount& account) {
+    for (int i = 0; i < 500; ++i) {
+        account.withdraw(1); 
+    }
+}
+
+int main() {
+    BankAccount account;
+
+    thread t1(deposit_to_account, ref(account));
+    thread t2(withdraw_from_account, ref(account));
+    thread t3(deposit_to_account, ref(account));
+    thread t4(withdraw_from_account, ref(account));
+
+    t1.join();
+    t2.join();
+    t3.join();
+    t4.join();
+
+    cout << "Final balance: " << account.get_balance() << endl;
+
+    return 0;
+}