digits

I'm trying to find an algorithm which "breaks the safe" by typing the keys 0-9. The code is 4 digits long. The safe will be open where it identifies the code as substring of the typing. meaning, if the code is "3456" so the next typing will open the safe: "123456". (It just means that the safe is not restarting every 4 keys input). Is there an algorithm which every time it add one digit to the sequence, it creates new 4 digits number (new combinations of the last 4 digits of the sequence\string)? thanks, km. Editing (I post it years ago): The question is how to make sure that every time I set

How can we find the number of numbers less than a given number with no repeating digits in it? For example the number of such numbers less than 100 is 90. (11, 22, 33,44, 55,66,77,88,99 have repeating digits so are excluded). Similarly for less than 1000, digits like 101, 110, 122, 202 etc have to be excluded. donebizkit Here is a way to make it quicker. Notice that there is a correlation between the number of digits in the max number and the solution (number of numbers which I will call NON ) 100 (3 digits) => NON = 10 * 9 1000 (4 digits) => NON = 10 * 9 * 8 10000 (5 digits) => NON = 10 * 9 *

I was recently making a program which needed to check the number of digits in a number inputted by the user. As a result I made the following code: int x; cout << "Enter a number: "; cin >> x; x /= 10; while(x > 0) { count++; x = x/10; } From what I can tell (even with my limited experience) is that it seems crude and rather unelegant. Does anyone have an idea on how to improve this code (while not using an inbuilt c++ function)? In your particular example you could read the number as a string and count the number of characters. But for the general case, you can do it your way or you can use a

I was looking for a quick PHP function that, given a string, would count the number of numerical characters (i.e. digits) in that string. I couldn't find one, is there a function to do this? This can easily be accomplished with a regular expression. function countDigits( $str ) { return preg_match_all( "/[0-9]/", $str ); } The function will return the amount of times the pattern was found, which in this case is any digit. first split your string , next filter the result to only include numeric chars and then simply count the resulting elements. <?php $text="12aap33"; print count(array_filter

if i just read my sum_digits function here, it makes sense in my head but it seems to be producing wrong results. Any tip? def is_a_digit(s): ''' (str) -> bool Precondition: len(s) == 1 Return True iff s is a string containing a single digit character (between '0' and '9' inclusive). >>> is_a_digit('7') True >>> is_a_digit('b') False ''' return '0' <= s and s <= '9' def sum_digits(digit): b = 0 for a in digit: if is_a_digit(a) == True: b = int(a) b += 1 return b For the function sum_digits , if i input sum_digits('hihello153john') , it should produce 9 Notice that you can easily solve this

I found this code for making my textbox only accept numbers. Private Sub TextBox1_KeyPress(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress Dim allowedChars As String = "0123456789" If allowedChars.IndexOf(e.KeyChar) = -1 Then ' Invalid Character e.Handled = True End If End Sub But... the user can't delete the numbers using the backspace button. How do I do then? You also need to handle pasted text (there may not be a keypress). The best way to do this is with a MaskedTextBox . LV Ganesh Private Sub txtValue_KeyPress(ByVal sender As