added Day 17 (#308)

* added Day16

* added function overloading

* added operator overloading

* added Day17

* added exception handling

docs/Day 17/_category.json

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+{
+ "label": "Day 17",
+ "position": 17,
+ "link": {
+ "type": "generated-index"
+ }
+ }

docs/Day 17/exception-handling.md

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+---
+sidebar_position: 1
+title: "Exception Handling in C++"
+description: "Exception Handling provides a mechanism to handle unexpected situations (exceptions) that occur during the execution of a program, ensuring that the program can continue to operate or fail gracefully."
+sidebar_label: "Exception Handling"
+slug: exception-handling-in-cpp
+---
+
+# Exception Handling in C++
+
+Exception handling in C++ is a powerful feature that allows developers to manage and respond to runtime errors in a controlled way. It provides a mechanism to handle unexpected situations (exceptions) that occur during the execution of a program, ensuring that the program can continue to operate or fail gracefully.
+
+It enables a program to deal with anomalies and unexpected conditions in a consistent and manageable way. It allows developers to separate error-handling code from regular code, improving readability and maintainability.
+
+## Basics of Exception Handling
+The basic concept of exception handling involves three keywords: `try`, `throw`, and `catch`.
+
+1. **try:** The try block contains the code that may potentially throw an exception.
+2. **throw:** The throw keyword is used to signal the occurrence of an anomaly or exceptional condition.
+3. **catch:** The catch block handles the exception thrown by the throw statement.
+
+```cpp
+#include <iostream>
+using namespace std;
+
+int main() {
+ try {
+  // Code that may throw an exception
+  throw 20;
+ }
+ catch (int e) {
+  // Code that handles the exception
+  cout << "An exception occurred. Exception Nr. " << e << endl;
+ }
+ return 0;
+}
+```
+
+## Exception Handling Mechanism
+
+The exception handling mechanism in C++ involves the following steps:
+1. **Throwing an Exception:** When an error occurs, the program throws an exception using the throw keyword.
+2. **Catching the Exception:** The thrown exception is caught by a catch block that matches the type of the exception.
+3. **Handling the Exception:** The catch block contains code to handle the exception.
+
+### Throwing Exceptions
+An exception can be thrown using the throw keyword followed by an exception object. This object can be of any type, including built-in types or user-defined types.
+
+```cpp
+#include <iostream>
+using namespace std;
+
+void test(int x) {
+ if (x == 0) {
+ throw "Division by zero condition!";
+ }
+}
+
+int main() {
+ try {
+ test(0);
+ }
+ catch (const char* msg) {
+ cout << "Caught: " << msg << endl;
+ }
+ return 0;
+}
+```
+
+### Catching Exceptions
+The catch block is used to handle exceptions. It must follow a try block. The parameter of the catch block determines the type of exception it can handle.
+
+```cpp
+#include <iostream>
+using namespace std;
+
+int main() {
+ try {
+ throw 100;
+ }
+ catch (int e) {
+ cout << "An exception occurred. Exception Nr. " << e << endl;
+ }
+ return 0;
+}
+```
+
+### Multiple Catch Blocks
+A single try block can have multiple catch blocks to handle different types of exceptions.
+
+```cpp
+#include <iostream>
+using namespace std;
+
+int main() {
+ try {
+  throw 100.5;
+ }
+ catch (int e) {
+  cout << "Caught an integer exception. Exception Nr. " << e << endl;
+ }
+ catch (double e) {
+  cout << "Caught a double exception. Exception Nr. " << e << endl;
+ }
+ return 0;
+}
+```
+
+### Standard Exception Classes
+C++ provides a set of standard exception classes defined in the `<stdexcept>` header file. Some of the commonly used standard exception classes are:
+
+1. `std::exception`: Base class for all standard exceptions.
+2. `std::bad_alloc`: Thrown by new on allocation failure.
+3. `std::bad_cast`: Thrown by dynamic_cast when it fails with a reference type.
+4. `std::bad_typeid`: Thrown by typeid.
+5. `std::logic_error`: Represents logic errors.
+6. `std::runtime_error`: Represents runtime errors.
+
+
+### User-Defined Exceptions
+You can define your own exception classes by inheriting from the std::exception class or any of its derived classes.
+
+```cpp
+#include <iostream>
+#include <exception>
+using namespace std;
+
+class MyException : public exception {
+ virtual const char* what() const throw() {
+ return "My custom exception occurred";
+ }
+};
+
+int main() {
+ try {
+ throw MyException();
+ }
+ catch (MyException& e) {
+ cout << e.what() << endl;
+ }
+ return 0;
+}
+```
+
+### Stack Unwinding
+When an exception is thrown, the stack unwinding process occurs. It means the destructor of each object is called for all objects constructed since the entry to the try block.
+
+```cpp
+#include <iostream>
+using namespace std;
+
+class Test {
+public:
+ Test() { cout << "Constructor called" << endl; }
+ ~Test() { cout << "Destructor called" << endl; }
+};
+
+int main() {
+ try {
+ Test t;
+ throw 20;
+ }
+ catch (int e) {
+ cout << "Caught " << e << endl;
+ }
+ return 0;
+}
+```
+
+## Best Practices
+1. **Use Exceptions for Exceptional Conditions:** Exceptions should represent unexpected conditions, not regular control flow.
+2. **Catch Specific Exceptions:** Catch specific exceptions to handle different error conditions appropriately.
+3. **Resource Management:** Use RAII (Resource Acquisition Is Initialization) to manage resources, ensuring they are released even when exceptions occur.
+4. **Minimize Exception Usage in Destructors:** Destructors should not throw exceptions to avoid unexpected behavior during stack unwinding.
+5. **Document Exception Specifications:** Clearly document the exceptions that functions might throw.
+
+By understanding and effectively using exception handling in C++, you can write more robust and maintainable code, ensuring your programs can gracefully handle unexpected conditions and errors.