- 48e-Get-Valid-Int-(Reusable-Function-Version).7z
- 48f-Get-Valid-Int-(Unit-Test-Version).7z

I know I should really have multiple projects in the same workspace to perform unit tests but I’m getting towards the end of it…

If you have the time to take a quick swiz (they’re both Code::Blocks projects) and let me know if I’ve got the right end of the stick or if I’ve got the wrong stick entirely (which is the feeling I’ve got) then it would be greatly appreciated – no worries if not tho, I know you’re a busy bloke!

/me hangs up his coding hat for the day…

However it is preferable when developing functions like this to not output anything, they should be like submarines… silent running.

The CALLING function should deal with IO, the LIBRARY function should deal with parsing the integer or whatever needs to be done. Exceptions should be used when things go wrong, then the calling function can do what is required.

After all, the calling function may need to do different things depending on its context. The library function will have no idea what that could possibly be as it will be impossible to predict all scenarios.

You will then be able to use the function for command line utilities, Windows Framework applications, QT, etc, etc.

#include <iostream>
#include <limits>
using namespace std;
 
int getValidInt(int min, int max)
{
	int number;
 
	while ( (cout << "Enter a valid number: " && !(cin >> number) )  || (number < min) || (number > max) || cin.peek() != '\n')
	{
		cout << "You must input a whole number between " << min << " and " << max << endl;
		cin.clear();
		cin.ignore(numeric_limits<streamsize>::max(), '\n');
	}
 
	return number;
}
 
int main()
{
	int x = getValidInt(1, 100);
 
	cout << "Successfully got the valid integer value: " << x << endl;
 
	return 0;
}

Still lovin’ it =D

With the code above tho the guy messed up and added two cin.ignore() statements so you need to push enter after each failed entry, I just did a quick mod to fix and added a top validation limit, which gives us this:

#include <iostream>
#include <limits>
using namespace std;
 
int main()
{
    const int MIN = 1;
    const int MAX = 100;
    int number;
 
    while ( (cout << "Enter a valid number: " && !(cin >> number) )  || (number < MIN) || (number > MAX) || cin.peek() != '\n')
    {
        cout << "You must input a whole number between 1 and 100!" << endl;
        cin.clear();
        cin.ignore(numeric_limits<streamsize>::max(), '\n');
    }
 
    cout << "Successfully got the valid integer value: " << number << endl;
 
    return 0;
}

That works beautifully, and saves 130 lines of clumsiness! I think you’ve unlocked an achievement!

=D

while (cout << "Enter Quantity: " && !(cin >> Quantity)  || (Quantity < 1) || cin.peek() != '\n')
{    
	cout << "Quantity must be  whole positive number!" << endl;    
	cin.clear();
	cin.ignore();
	cin.ignore(numeric_limits<streamsize>::max(), '\n');
}

Apologies if I messed up the markup code

(r3dux: All good! It’s “cpp” for C++, list of valid languages for highlighting plus examples can be found here)