How to prevent a user to enter a space between characters and numbers

[GregThomas12]

Hi, I'm trying to prevent the user to input a space between characters or numbers. The user can only enter 15 character with any combination with numbers. Any ideas on how to do it? this is my code:
if (input.length() <= 15) {
index = 0;
do {
// check if characters are letters and digits
for (int i = 0; i < input.length(); i++){

if (!(isalpha(input[i])) && (!(isdigit(input[i]))) && ((isspace(input[i]))) )
valid = false;
else
valid = true;
index++;

}

[Renthalkx97]

As far as I know you can't prevent them from not typing something (maybe some OS specific function to manipulate the console can?), but you can format what they type to your liking.

Example:

#include <iomanip>
#include <iostream>
#include <string>

int main()
{
	std::string str = "This String Has Spaces!";

	std::cout << "Unformatted string: " << str << "\n\n";

	std::streamsize pos;

	while ((pos = str.find_first_of(' ')) != std::string::npos)
	{
		str.erase(pos, 1);
	}

	std::cout << "Formatted string: " << str;

	return 0;
}

[GregThomas12]

You comment "As far as I know you can't prevent them from not typing something" is funny
I was talking in software terms, not mechanical !

[Renthalkx97]

I meant software-wise. On windows you can hook into the console and do all sorts of stuff. I'm not sure if what you want is something you can do though.