Handling Data type mismatch exception

Hello!
I have a problem with being able to take care of run-time errors where the user types in data different than the one expected. For example, an integer is expected, but (maybe) the user enters a string. In my console programs, when this happens, I just get a whole lot of junk printed on my screen. How can I take care of this, such that an error message is displayed when this happens, instead of the whole program going to trash? Please, I need help urgently!

 

sir
please send ur program and its corresponding output
so that we can try to explain it

 

Here it is:

Code:

#include <iostream>

using namespace std;

int main()
{
    try
    {
    cout << "Please enter the number of values in the Fibonacci series that you want: ";
    int n; cin >> n;
    n = static_cast<int>(n);
    if (n < 1)
    throw "You dey craze?!\nIn fact, I don vex!\nBye bye [:-(]";
    if (n == 1)
    cout << "The series is as follows: " << 1;
    else
    {
        int p = 1, pp = 0, w;
        cout << "\nThe series is as follows: ";
        for (int i = 0; i < n; i++)
        if(i%2 == 0)
        {
            p = p + pp;
            cout << p << " ";
        }
        else
        {
            pp = pp + p;
            cout << pp << " ";
        }

    }
    }
    catch (const char aMessage[])
    {
        cout << endl << aMessage << endl;
    }
    return 0;
}

Well, when any number is typed, the fibonacci series is produced to that nth number.
However, if a string, or a character is entered, the program begins to flood the screen with some junk output continuously, and does not end, unless forced to. What can i do?

 

sir
we know that characters are stored as integers
when u enter a character it will go for its corresponding ascii value and it will proceed further
use ctrl+pause/break in keyboard to come for junk output

 

Yeah, I know, but if you look at the code, you will find out that I used the try-throw-catch method to take care of the case where the user enters a negative number. Now, what I want is a method to, instead of leaving the program to go into an infinite loop, display an error message and then, maybe resume, or end the program.

 

Try it...

Code:

#include<iostream.h>
#include<string.h>
#include<conio.h>
main()
{
int n;
cout << "Please enter the number of values in the Fibonacci series that you want: ";
cin >> n;
     if(!isdigit(y))
     cout << "It's a string,please enter a number";
cout << '\n';
getch();
}

 

Try it...

Code:

#include<iostream.h>
#include<string.h>
#include<conio.h>
main()
{
int n;
cout << "Please enter the number of values in the Fibonacci series that you want: ";
cin >> n;
     if(!isdigit(y))
     cout << "It's a string,please enter a number";
cout << '\n';
getch();
}

 

how about preventing a stream error?

Code:

#include <iostream> 
#include <sstream>
#include <string> 

int main() {

	std::string input;
	std::istringstream ss;
	int num;

	do {

	    num = -1;

	    std::cout << "Enter positive number: ";
            std::cin >> input;

	    ss.clear();
	    ss.str(input);

	    if(!(ss >> num))
	        std::cout << "garbage input: " << input << "\n";

	} while(num < 0);

	while(std::cin.get() != '\n')
		;

	std::cout << "num = " << num;
	std::cin.get(); 

	return 0;
}