How to disallow characters

[Frypot]

Hi, i have received a task for extended study to write a program in C++ that will allow you to enter 5 single digit numbers. So far the program to ONLY allow single digit numbers.

Here is my code and any help would be greatly appreciated.

#include <iostream>
#include <string>

using namespace std;

int main()
{


	int number[5];
	int i;

	for(i=0;i<=4;i++)
	{
		cout<<"Please enter a single didgit number : "<< endl;
		cin>>number[i];
	}
	for(i=0;i<=4;i++)	
	{
		cout<<"The five numbers you chose where : "<< number[i] <<endl;

	}

	system("pause");
	

}

Thanks

[Catfish]

You don't need the string header.
Add a check to reject numbers:

cout<<"Please enter a single didgit number : "<< endl;
cin >> number[i];

while (number[i] >= 10 || number[i] <= -10)
{
    cout << "Not a single digit number, try again: ";
    cin >> number[i];
}

[Da0omph]

Sorry, I seem to be drawing blank. What is it that you need help with?

[Frypot]

Da0omph >>

Hi basically i need the program shown to display a message when an incorrect symbol (I.e. Not a number between 0 and 9) is entered and ask the user to enter a valid number.

Catfish >>

Hey i have a variation of this myself however it just causes the program to break and display;

"Not a single digit number, try again: "

over and over again. Is there anything i have missed including the while loop as shown?

#include <iostream>
using namespace std;

int main()
{


	int number[5];
	int i;

	for(i=0;i<=4;i++)
	{
		cout<<"Please enter a single digit number : "<< endl;
		cin>>number[i];

		while (number[i] >= 10 || number[i] <= -10)
		{
			cout<<"Not a single digit number, try again: "<<endl;
			cin>>number[i];
		}

	}
	for(i=0;i<=4;i++)	
	{
		cout<<"The five numbers you chose where : "<< number[i] <<endl;

	}

	system("pause");
	
	

}

[Catfish]

You changed the topic subject, right? I don't remember it was about disallowing characters.

Anyway, here's what you can do:

* Use std::string and read a string, using getline().
* Check if the string has length equal to one, otherwise reject it.
* Use isdigit() to see if it's a digit.
* Make a stringstream out of the string in order to read the number itself.

#include <iostream>
#include <string> // for string and getline()
#include <cctype> // for isdigit()
#include <sstream> // for using >> on the contents of a string

using namespace std;

int main()
{
    int number[5];
    int i=0;
    string temp;

    while (i < 5)
    {
        cout<<"Please enter a single digit number : ";
        getline(cin, temp); // this will also read spaces, unlike cin>>

        bool finished=false;

        while (finished == false)
        // we dont need { and } if we have only one instruction in: if, else, for, while or do
        // (here if-else counts as a single instruction)
            if (temp.length() == 1 && isdigit(temp[0]) != 0) // good value, add it
            {
                stringstream temp_stream(temp); // with a stringstream we can use
                temp_stream >> number[i++]; // a string as if it's a file
                finished=true; // we're done reading, exit the little while()
            }
            else // not a good value, read again
            {
                cout<<"Not a single digit number, try again: ";
                getline(cin, temp);
            }
    }

    for(i=0; i<=4; ++i) // curly braces not needed for single instructions
        cout<<"The five numbers you chose were : "<< number[i] <<endl;

    system("pause");
}