In what circumstances we need to use Exception Handling Mechanism. Discuss with example.

 Exception Handling Mechanism is used to handle the exceptional conditions that can arise during the execution of a program. These exceptional conditions can be runtime errors like division by zero, out of memory, etc. or user-defined errors like invalid input. The main purpose of using exception handling is to provide a way to gracefully handle these errors instead of crashing the program.

Let's consider an example where we need to use exception handling. Suppose we have a program that asks the user to enter two numbers and then divides the first number by the second number. If the second number is zero, the program will encounter a runtime error of division by zero. Instead of crashing the program, we can use exception handling to gracefully handle this error.

#include <iostream>
using namespace std;
int main() {
   int num1, num2, result;
   cout << "Enter two numbers: ";
   cin >> num1 >> num2;
   try {
      if (num2 == 0)
         throw "Divide by zero exception";
      result = num1 / num2;
      cout << "Result = " << result << endl;
   }
   catch(const char* msg) {
      cerr << msg << endl;
   }
   return 0;
}