Thread: scanning for numbers - not letters

Code:

#include <iostream>
using namespace std;

int main()
{
	int array[10];

	int i = 0;
	int count = 0;

	cout << "Enter up to ten numbers" << endl;

    while (cin >> array[i++] && i < 10)
	{
		while (isalpha(array[i]))
			cout << "Don't enter letters" << endl;
		    
		count++;
	}

	cout <<"\nYour numbers are:" << endl;

	for (i = 0; i < count; i++)
		cout << array[i] << endl;

	return 0;

 }

The array only holds numbers, so if a letter or anything else is entered, the program immediately exits.

How do I detect if a number wasn't entered? isalpha isn't working.

example

Code:

#include "stdafx.h"
#include <iostream>

using namespace std;


int main(int argc, char* argv[])
{
	int age;

	while (cout << "Enter age: " && !(cin >> age) || (age < 1 || age > 100))
	{
		cout << "\nInvalid input or out of range\n";
		cin.clear();
		cin.ignore();
	}
		cout << "An integer was recieved!" << endl;

		cout << age << endl;

	return 0;
}

As usual...isn't there an easier way to do that? I know nothing about argc and argv.

I want an easy example like this:

Code:

cout << "Enter a number" << endl;
cin  >> number;

(if number != *a number*) //I'm not sure how to do this part
cout << "You didn't enter a number" << endl;

else
cout << "You entered a number!" << endl;

>> I know nothing about argc and argv.

They have nothing to do with checking the input, those are main arguments. Just pay attention too

Code:

while (cout << "Enter age: " && !(cin >> age)

I forgot i had a range check in there. This line checks for valid user input. This is how i do it, i dont know any other ways, this is a played out topic, search it.

he was having problems with isalpha, therefore i didnt suggest it. Also, i do believe my method can be used for any data type.

isalpha() is meant to check to see if a char entered is within the ASCII range of 'A'-'z'. So isalpha(67) will actually return true. It isn't meant to check integers to see if a number or character was entered, you will still get the same error and problem (and probably more!) that you would get without it.