getche() and ASCII

[Chaplin27]

Hello,
I have a quick question to ask...let's say I'm accepting user input with getche() and placing the input in a char...then I'm trying to convert the char digit into a numerical digit...is there any way to do that?

[Lithorien]

Yep.

C way: (int)YourVariable.

C++ way: static_cast<int>(YourVariable)

[Chaplin27]

thanks for the info lith...I'll see what I can do with it...much appreciated Chap

[Lithorien]

One of your major problems is that the char will only hold one # of a number like 15, and read in the 1 and 5 seperately. It's impossible to defeat your while() loop like that.

Ok. I'm going to rewrite your function to be standard (read: portable). conio isn't available to all compilers.

See if this code makes sense to you..

#include <iostream>

int main()
{
	char chNumber[2]; // We need this to handle numbers in the more-than-single digit range. Otherwise your while loop will loop forever.
	
	while (1) // Loop forever.. we handle invalid numbers below.
	{		
		std::cout << "Enter a number: ";
		std::cin >> chNumber;
		
		if ((chNumber[1] != '\0') || (chNumber[0] < '0') || (chNumber[0] > '9')) // If, for some reason, the number is invalid..
		{
			std::cout << "\nInvalid number."; // Tell them, and..
			break; // Quit the while loop.
		}
		
		std::cout << "\nASCII number is: " << static_cast<int>(chNumber[0]) << "\n\n"; // Else print the ASCII value.
	}
	
	std::cin.ignore(80, '\n');
	std::cin.get();
	return(0);
}

[Hunter2]

>>then I'm trying to convert the char digit into a numerical digit
Not sure if your problem's been solved already or not, but if you're trying to convert '9' into the integer 9, then what you want is:

int theDigit = theChar - '0';

Cheers

**EDIT**

#include <cctype>

//(chNumber[1] != '\0') || (chNumber[0] < '0') || (chNumber[0] > '9')
//Replace with:
std::isdigit(chNumber[0])

If I'm not mistaken, if chNumber[1] != '\0' then you've already got an index out-of-bounds error. A better solution would probably be to use std::getline() to read into a std::string first, and then check to see if the size is greater than 1. Then, the testing for chNumber[0] < '0' etc. can be replaced by std::isdigit(), which is found in <cctype>.

[Lithorien]

Nice and elegant fix, Hunter.

I was going the string route, but just wasn't sure how to handle it. Thanks!