EXCEPTIONAL HANDLING PROGRAMS

DIFFERENT EXCEPTIONAL HANDLING PROGRAMS

BAD-ALLOC EXAMPLE:-

// bad_alloc example

#include <iostream>     // std::cout

#include <new>          // std::bad_alloc

int main () {

  try

  {

    int* myarray= new int[10000];

  }

  catch (std::bad_alloc& ba)

  {

    std::cerr << "bad_alloc caught: " << ba.what() << '\n';

  }

  return 0;

}

BAD-CAST EXAMPLE:-

// bad_cast example

#include <iostream>       // std::cout

#include <typeinfo>       // std::bad_cast

class Base {virtual void member(){}};

class Derived : Base {};

int main () {

  try

  {

    Base b;

    Derived& rd = dynamic_cast<Derived&>(b);

  }

  catch (std::bad_cast& bc)

  {

     std::cerr << "bad_cast caught: " << bc.what() << '\n';

  }

  return 0;

}

BAD-EXCEPTION EXAMPLE:-

//Exception Handling: Use of built-in exception class

#include<iostream>

#include<exception> //header file of exception class

using namespace std;

int main()

{

      int *a;

      long n;

      cout<<"\nEnter no. of values:";

      cin>>n;

      try

      {

            a = new int[n]; //exception will be thrown by default if the n exceeded memory limit

            cout<<"Array created in memory for "<<n<<" elements.";

            delete a;

      }

      catch(bad_alloc e) //or catch (exception e)

      {

            cout<<"\n** Error: "<<e.what();

      }

}

INVALID-ARGUMENT EXAMPLE:-

// invalid_argument example

#include <iostream>       // std::cerr

#include <stdexcept>      // std::invalid_argument

#include <bitset>         // std::bitset

#include <string>         // std::string

int main (void) {

  try {

    // bitset constructor throws an invalid_argument if initialized

    // with a string containing characters other than 0 and 1

    std::bitset<5> mybitset (std::string("01234"));

  }

  catch (const std::invalid_argument& ia) {

        std::cerr << "Invalid argument: " << ia.what() << '\n';

  }

  return 0;

}

STANDARD EXCEPTION EXAMPLE:-

//  standard exception

#include <iostream>

#include <exception>

using namespace std;

int main () {

  try

  {

    int* myarray= new int[1000];

  }

  catch (exception& e)

  {

    cout << "Standard exception: " << e.what() << endl;

  }

  return 0;

}

LENGTH ERROR EXAMPLE:-

// length_error example

#include <iostream>       // std::cerr

#include <stdexcept>      // std::length_error

#include <vector>         // std::vector

int main (void) {

  try {

    // vector throws a length_error if resized above max_size

    std::vector<int> myvector;

    myvector.resize(myvector.max_size()+1);

  }

  catch (const std::length_error& le) {

        std::cerr << "Length error: " << le.what() << '\n';

  }

  return 0;

}

LOGICAL ERROR EXAMPLE:-

//range error when input value a=

#include<iostream>

using namespace std;

int main()

{

     int a, b, c;

      cout<<"\nEnter two numbers: ";

      cin>>a>>b;

      try

      {

            if(b==0) throw 0;

            c = a/b;

            cout<<"\nDivision result is: "<<c;

      }

      catch(int)

      {

         cout<<"\nError: out of range of integer";

      }

}

OUT OF RANGE EXAMPLE:-

// out_of_range example

#include <iostream>       // std::cerr

#include <stdexcept>      // std::out_of_range

#include <vector>         // std::vector

int main (void) {

  std::vector<int> myvector(10);

  try {

    myvector.at(20)=100;      // vector::at throws an out-of-range

  }

  catch (const std::out_of_range& oor) {

    std::cerr << "Out of Range error: " << oor.what() << '\n';

  }

  return 0;

}

RUN-TIME ERROR:-

//Basic Use of try-catch

#include<iostream>

using namespace std;

int main()

{

      int a, b, c;

      cout<<"\nEnter two numbers: ";

      cin>>a>>b;

      try

      {

            if(b==0) throw 0;

            c = a/c;

            cout<<"\nDivision result is: "<<c;

      }

      catch(int)

      {

         cout<<"\nError: Divide by Zero";

      }

}

EXCEPTION MULTIPLE CATCH BLOCKS:-

//Exception handling: Multiple catch blocks

#include<iostream>

using namespace std;

int main()

{

      int a, b, c;

      cout<<"\nEnter two numbers: ";

      cin>>a>>b;

      try

      {

            if(a==0 and b==0) throw (float)0;

            if(b==0) throw (int)0;

            c = a/b;

            cout<<"\nDivision result is: "<<c;

      }

      catch(int)

      {

         cout<<"\nError: Divide by Zero: Result is INFINITY";

      }

      catch(float)

      {

         cout<<"\nError: Divide by Zero: Result is NaN";

      }

}

SINGLE CATCH BLOCK EXAMPLE TO HANDLE MULTIPLE ERROR:-

//Exception handling: single catch block to handle multiple errors using error codes

#include<iostream>

using namespace std;

int main()

{

      int a, b, c;

      cout<<"\nEnter two numbers: ";

      cin>>a>>b;

      try

      {

            if(a==0 and b==0) throw 2;

            if(b==0) throw 1;

            c = a/b;

            cout<<"\nDivision result is: "<<c;

      }

      catch(int& errorcode)  //can also work without &

      {

        if(errorcode==1)

               cout<<"\nError: Divide by Zero: Result is INFINITY";

            else

               cout<<"\nError: Divide by Zero: Result is NaN";

      }

}

USE OF BUILT-IN EXCEPTION CLASS:-

//Exception Handling: Use of built-in exception class

#include<iostream>

#include<exception> //header file of exception class

using namespace std;

int main()

{

      float a, b;

      cout<<"\nEnter two numbers:";

      cin>>a>>b;

      try

      {

            if(b==0) throw exception();

            cout<<"Division is "<<a/b;

      }

      catch(exception e)

      {

            cout<<"\n** Error: "<<e.what();

      }

}

USER-DEFINED EXCEPTION CLASS:-

//Exception Handling: user-defined exception class

#include<iostream>

#include<exception> //header file of exception class

using namespace std;

class DivByZero: public exception

{

      public:

            //override the what function declared in exception class with header as:

            //    virtual const char* what() const throw() { }

            //or simply with th header as under:

            char* what()

            {

                  return "Divide by Zero."; //error message that you want to send

            }

};

int main()

{

      float a, b;

      cout<<"\nEnter two numbers:";

      cin>>a>>b;

      try

      {

            if(b==0) throw DivByZero();

            cout<<"Division is "<<a/b;

      }

      catch(DivByZero e)

      {

            cout<<"\n** Error: "<<e.what();

      }

}