using exception on switch case

[fishsticks00]

I get an infinite loop if i enter a char/string during the switch statement, so i made an exception to catch anything other then integers (line 155). But, i still get the infinite loop. I may be doing something wrong so any help would be great.

#include <iostream>
#include <string>
#include <conio.h>
#include <exception>
#include <typeinfo>
using namespace std;

class list
{
private:
	struct node
	{
		string data;
		node *next;
	}*head, *tail;

public:
	list() : head(0), tail(0) {}
	~list();
	void push_front(string &d);
	void push_back(string &d);
	bool isempty() const;
	bool pop_back(string &d);
	bool pop_front(string &d);

	friend ostream &operator<<(ostream &, list &);
};

list::~list()
{
	node *temp = head;
	node *tmp;

	while(temp != 0)
	{
		tmp = temp;
		temp = temp->next;
		delete tmp;
	}
}

bool list::isempty() const
{
	return head == 0;
}

void list::push_front(string &d)
{
	node *temp = new node;
	temp->data = d;
	temp->next = 0;

	if(isempty())
		head = tail = temp;
	else
	{
		temp->next = head;
		head = temp;
	}
}

void list::push_back(string &d)
{
	node *temp = new node;
	temp->data = d;
	temp->next = 0;

	if(isempty())
		head = tail = temp;
	else
	{
		tail->next = temp;
		tail = temp;
	}
}

bool list::pop_front(string &d)
{
	if(isempty())
		return false;
	else
	{
		node *temp = head;

		if(head == tail)
			head = tail = 0;
		else
			head = head->next;

		d = temp->data;
		delete temp;
		return true;
	}
}

bool list::pop_back(string &d)
{
	if(isempty())
		return false;
	else
	{
		node *temp = tail;

		if(head == tail)
			head = tail = 0;
		else
		{
			node *current = head;

			while(current->next != tail)
				current = current->next;

			tail = current;
			current->next = 0;
		}

		d = temp->data;
		delete temp;
		return true;
	}
}

ostream &operator<<(ostream &output, list &L)
{
	list::node *temp = L.head;

	while(temp != 0)
	{
		output << temp->data << endl;
		temp = temp->next;
	}

	return output;
}

int main()
{
	list LL;
	int choice;
	string name;
	int temp;

	try
	{
		do
		{
			cout << "Enter choice: " << endl;
			cout << "1. Push_front." << endl;
			cout << "2. Push_back." << endl;
			cout << "3. Pop_front." << endl;
			cout << "4. Pop_back." << endl;
			cout << "5. Quit." << endl;
			cout << "$ ";
			cin >> choice;
			if(typeid(choice) != typeid(temp))
				throw;
			else
			{
				switch(choice)
				{
				case 1:
					cout << "Enter name to save" << endl;
					cout << "$ ";
					getline(cin, name);
					getline(cin, name);
					LL.push_front(name);
					cout << LL;
					break;

				case 2:
					cout << "Enter name to save" << endl;
					cout << "$ ";
					getline(cin, name);
					getline(cin, name);
					LL.push_back(name);
					cout << LL;
					break;

				case 3:
					LL.pop_front(name);
					cout << LL;
					break;

				case 4:
					LL.pop_back(name);
					cout << LL;
					break;

				case 5:
					break;
				}
			}
			
		}while(choice != 5);
	}catch(...)
	{
		cout << endl << endl;
		cout << "error... the choice is not on the system." << endl;
		_getch();
	}

	return 0;
}

[Bench82]

you've declared both choice and temp as int therefore the expression if(typeid(choice) != typeid(temp)) will always be false.

typeid is an operator which determines the static type of a variable at compile time, it has no knowledge of anything you do at runtime (such as user input), so it can't help you.

If you use cin >> choice and the user types in something which won't fit into an int variable, then the internal "fail" flag which belongs to cin will be set to true, and you'll not be able to do anything with cin until you've cleared the error state and discarded whatever bad data was waiting for you.

One option would be to perform your check as you're getting the data with if( cin >> choice ) then if it fails, use a combination of clear() to reset the state and ignore() to discard any bad data left waiting for you:

std::cin.clear();
std::cin.ignore( std::numeric_limits<std::streamsize>::max(), '\n' );

Although letting cin fail in the first place usually isn't ideal IMO; A better way would be to use a string, which is capable of storing any kinds of characters (cin is less likely to fail if you're getting a string), then do a checked conversion using a local stringstream object instead.
This has the advantage of avoiding the need to reset cin every time (it shouldn't matter if a local stringstream object has its fail flag set)

Example of a reliable checking/conversion function using a stringstream:

bool convert( const std::string& str, int& n )
{
    std::istringstream buffer( str );
    bool success = false;
    if( buffer >> n )
    {
        success = true;
    }
    return success;
} 

[fishsticks00]

Thanks for the reply, i tried the if(!(cin >> choice)) way, but i got a big error. And im not sure how to implement the bool convert(const std::string& str, int& n); option. I understand how it works, but why would i enter a string and a number? also, i can't use strings in the switch case.

[fishsticks00]

Nevermind i got the if(!(cin >> choice)) way to work. thank you for the help!