[ayabrego]

Hey there guys. I am creating a keypad that will output the corresponding letter to number. Kinda like a keypad on a cell phone. Well I am having trouble on validating the input from the user. The input has to be A to Z (not Z hence to not through)and not Q or any non letter. Whats wrong with my logic?

#include <iostream>
#include <conio.h>
#include <cctype>

using namespace std;



int main()
{
    int Response;
    
    cout << "Enter A Character\n";
    cin  >> Response;

    getch();

if (Response == 64 > 90 && Response != 81)// using asci but right here is the problem
   {
    cout << "good";
    getch();
}

    else{
    cout << "bad";
    getch();
}
return 0;
}

[JackOfAllTrades]

What is Response == 64 > 90 supposed to mean???

[ayabrego]

JackOfAllTrades, on 11 May 2011 - 08:31 AM, said:

What is Response == 64 > 90 supposed to mean???

Its suppose to mean A to Z. Response is a variable of the user input.

[JackOfAllTrades]

Does "response equals 64 greater than 90" make any sense to you in English?

[ayabrego]

JackOfAllTrades, on 11 May 2011 - 08:33 AM, said:

Does "response equals 64 greater than 90" make any sense to you in English?

Well then I am not sure on how to validate the user input. How can I say response equals A to z and not Q.

[r.stiltskin]

Deal with A-Z or a-z and not 'Q' and not 'q' separately.

Or use the isalpha function in <cctype>.

[sk1v3r]

if it is between a and z, then it is more than or equal to 'a', and less than or equal to 'z'

[RetardedGenius]

Your problem is in line 18:

if (Response == 64 > 90 && Response != 81)

That's not how boolean expressions are evaluated in an if statement, it simply means nothing. What you need to do is separate them into two different comparisons.

E.g to ensure that 5 ≤ x < 10 you would write the following:

if ( 5 <= x && x < 10)

You may find the code easier to understand if you put each separate boolean expression inside parenthesis i.e.

if ( (5 <= x) && (x < 10) )

Although this is not necessary, because of the hierarchy of operators.