infinite loop !

Hi, guys~

I just want to user input a number and then decide whether continue or not, but I met a infinite loop when testing it. my code is right below:

Code:

---

#include <iostream>

void main ()
{
    int x;
    while(1)
    {
        cout << "input a number: ";
        cin >> x;
        if (number==8)
        {
            break;
        }
    }
    //if break then go to next step;
}

---

it works fine when input a simply number, but that mess comes when your input a string like "relrejlre" etc. How to calm it down ???
:confused:

look at the "atoi" (alpha to integer) function, an integer cannot handle input other than a number, and will crash, whereas if you use atoi ( stdio.h or stdlib.h i think ) it will convert to 0.

I think that is what you mean.

i ran nito the same problem as you. Good coding practice would be to put the loop in a try/catch block...but my program was for a buddy at work, so i left him an "easter egg" so to speak.

Code:

---

while (int theNumber<24&&int infiniteLoopCount<20)
{
std::cout<<"enter a number between 1 and 24"<<endl;
std::cin>>theNumber;
infiniteLoopCount++;
}
if (infiniteLoopCount<=10)
{
std::cout<<"Oh no! You've been caught in the INFINITE LOOP OF DEATH!!!\nNext time enter a number, have a nice day."<<endl;
//delete pointers and junk
exit(1);
}

---

now like i said, that's not exactly good coding practice, but the guy i made it for wasn't very computer savvy, and the look on his face was priceless :). But if it's a formal app just go with the try/catch block....if you really want you can model it after the above while loop, then use a goto command to repeat it.

Code:

---

#include <iostream.h>

int main(void)
{
    int x;
    while (1)
    {
        cout << "input a number: ";
        cin >> x;
        if (!cin.good())
        {
            cin.clear();
            cin.ignore(10, '\n');
        }
        else if (x == 8) break;
    } 
}

---

This is better, IMHO:

Code:

---

#include <iostream.h>

int main(void)
{
    int x;
    while (1)
    {
        cout << "input a number: ";
        cin >> x;
        if (!cin.good())
        {
            //Clear all error flags
            cin.clear();
            //Remove all characters waiting to be read
            while (cin.rdbuf()->in_avail() > 0) cin.get();
        }
        else if (x == 8) break;
    } 
}

---

Quote:

---

Originally posted by Hammer

Code:

---

#include <iostream.h>

int main(void)
{
    int x;
    while (1)
    {
        cout << "input a number: ";
        cin >> x;
        if (!cin.good())
        {
            cin.clear();
            cin.ignore(10, '\n');
        }
        else if (x == 8) break;
    } 
}

---

---

thanx boys and girls~ :)

I just found cin.get and cin.ignore in my book, what about cin.good and cin.clear please £¿ :confused:

cin.good is what it says it is, if the input stream is good.
cin.clear does what it says, clears the input stream

it seems cin.clear and cin.good didnt works fine, what's the matter ? :confused: here is my code:

Code:

---

#include <iostream>

int i, j;

void main()
{
    while(1)
    {
            cout << "please input a number: ";
        cin >> i;
        if (!cin.good())
        {
                cin.clear();
        }
        else
        {
                if(i==8)
                {
                          cout << "good boy!";
                          break;
                  }
      }
    }
}

---