Getting stuck in infinite loop

Question

When I'm running this program for class, I'm getting stuck in an infinite loop whenever I enter a '|' character to end the while loop. I feel like I'm missing something obvious.

This problem is found on page 126 of Bjarne Stroustrup's C++ Programming book, but as a quick rundown, I'm just supposed to find the largest and smallest numbers that are typed in the by the user and return info on it. Typing in '|' is supposed to exit the loop so that I can get down to the part where it gives information about all the numbers inputted, but whenever I type that character (or any character that's not a number), it creates an infinite loop.

Here is my code.

int main()
{
    vector<double> nums;

    while (true)
    {
        double current_num;
        cout << "enter a double \n";
        cin >> current_num;
        if (current_num == '|')
            break;
        nums.push_back(current_num);
        sort(nums.begin(), nums.end());
        cout << nums[nums.size()-1] << " is the largest so far.\n";
        cout << nums[0] << " is the smallest so far.\n";
    }
    cout << nums[nums.size()-1] << " is the largest number.\n";
    cout << nums[0] << " is the smallest number.\n";
    cout << "Number of values entered: " << nums.size() << '\n';
    double sum = 0;
    for (int k = 0; k<nums.size(); ++k)
        sum += nums[0];
    cout << "Sum of all values: " << sum << '\n';
    for (int j=0; j<nums.size(); ++j)
        cout << nums[j] << ' ';
    return 0;
}

I was using VS13 in class and I wasn't having this problem, but now I'm coding in notepad++ and using PuTTY to compile at home (although I doubt this has anything to do with it).

Answer 1

You are comparing a character with a double here :

if (current_num == '|')

And this comparison will never do what you want it to do.

Read a character first, compare it with '|', then do a double conversion if necessary.

---

Note:

For your record the ASCII value of '|' is 124, so if you enter 124 your loop will end...