why is loop stuck

Question

Only problems remaining now are that my choice while loop is infinite since the break statements dont seem to be breaking out of the loop at all, so the program doesn't read the answer loop. Also, "Invalid Entry" displays every other incorrect input instead of displaying everytime an invalid character is entered

#include <iostream>
#include <cctype>
using namespace std;

int getAges(int age, const int SIZE);
char getChoice();
void displayInOrder(int numbers[], const int SIZE, char choice);
void displayInReverse(int numbers[], const int SIZE, char choice);

int main()
{
const int SIZE = 5;
int numbers[SIZE] = { 1, 2 ,3 ,4, 5 };
char answer = 0;
int age = 0;
char choice = 0;

while (choice = getChoice())
{
    if (toupper(choice) == 'O')
    {
        displayInOrder(numbers, SIZE, choice);
        break;
    }
    else if (toupper(choice) == 'R')
    {
        displayInReverse(numbers, SIZE, choice);
        break;
    }
    else
    {
        cout << "Invalid entry! - Must be O or R\n\n";
        break;
    }
}

while (toupper(answer) == 'Y')
{
    system("cls");

    age = getAges(age, SIZE);
    choice = getChoice();
    displayInOrder(numbers, SIZE, choice);
    displayInReverse(numbers, SIZE, choice);

    cout << "Run program again (Y or N)?  ";
    cin >> answer;

  if (toupper(answer) == 'N')
    {
        exit();
    }
}
return 0;
}

int getAges(int age, const int SIZE)
{
cout << "Enter " << SIZE << " ages: \n\n";
cin >> age;
cout << endl;
cin >> age;
cout << endl;
cin >> age;
cout << endl;
cin >> age;
cout << endl;
cin >> age;
cout << endl;
return age;
}

char getChoice()
{
char choice;
cout << "How do you want to see the ages displayed? \n\n Enter O for In Order, or R for In Reverse.\n\n";
cin >> choice;

return choice;

}

void displayInOrder(int numbers[], const int SIZE, char answer)
{
    cout << "Here are the ages in order: \n\n";
    for (int i = 0; i < SIZE; i++)
    {
        cout << numbers[i] << endl;
    }
}

void displayInReverse(int numbers[], const int SIZE, char answer)
{
    cout << "Here are the ages in reverse order: \n\n";
    for (int i = SIZE - 1; i >= 0; i--)
    {
        cout << numbers[i] << endl;
    }
}

Might no fix all your problems, but you're missing single quotes around `O` and `R`. — George, Nov 14 '17 at 22:13
Possible duplicate of [The Definitive C++ Book Guide and List](https://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list). — user0042, Nov 14 '17 at 22:15
What user0042 is trying to tell you is that your code is not even close to being valid C++. Rather than asking unanswerable questions on Stack Overflow you time would be better spent curling up with a good "C++ for Beginners" book (or web site.) — Dale Wilson, Nov 14 '17 at 22:18
If we were to just solve all of the compile errors, there's also a fair bit of ub, i'd be scared for my computer if I compiled and ran this... — George, Nov 14 '17 at 22:20
Updated my code: Only problems remaining now are that I'm not sure how to close the program if the user enters N for answer, and "Invalid Entry" displays every other incorrect input instead of displaying everytime an invalid character is entered. — Spencer Cumbie, Nov 14 '17 at 23:16

score 0 · Answer 1 · answered Nov 14 '17 at 23:44

0

1."Invalid Entry" displays every other incorrect input: you have a getChoice() call inside the while loop, here:

else
{
    cout << "Invalid entry! - Must be O or R\n\n";
    choice = getChoice();
}

which is followed by a getChoice() call in the

while (choice = getChoice())

Hence the previous getChoice() is not processed.

2."I'm not sure how to close the program if the user enters N for answer", You should think about if you can ever reach the second while loop and where you are setting the answer variable or basically where you are taking the user input for ending the program? You should see if it can it be taken care of in the first while loop ?

answered Nov 14 '17 at 23:44

tinus91

247
1
6
22

Easily the most effort put into helping me so far and I thank you for that. Removing `choice = get Choice();` in the else statement didn't change anything and for the second part are you saying try to put both while loops together inside main or try to put the if statement into the `answer` loop ? – Spencer Cumbie Nov 14 '17 at 23:54
First of all, removing `choice = get Choice();` in the else statement actually does take care of the alternating invalid type message. check: https://ideone.com/wt4Z86 – tinus91 Nov 15 '17 at 00:00
For the second part, you should check out how while loops work, your first loop is a never-ending loop. You should think about how to exit from that loop, at least. – tinus91 Nov 15 '17 at 00:06
Hmm, I believe you that it works but the invalid message still alternates. I even tried copy pasting the code from that link without any success, The break statements don't seem to be working either :( – Spencer Cumbie Nov 15 '17 at 00:31
Updated code with breaks and 2nd `choice = getChoice();` removed – Spencer Cumbie Nov 15 '17 at 00:56
For this code `while (toupper(answer) == 'Y')` where are you setting the answer variable/ where are you asking the user to enter the `answer` (Y/N). You should do something like `getAnswer()` similar to `getChoice()` to get user input for answer from answer. – tinus91 Nov 15 '17 at 08:23

why is loop stuck

1 Answers1