Thread: Reading in a number backwards!

  1. #1
    Registered User
    Join Date
    Oct 2002

    Reading in a number backwards!


    I have to write a program that will take a binary number (10010111) and then tell it decimal equivalency. But i do not know how to read in a number backwards. I know how to read them in one at a time from left to right but not right to left like i need to.

    Any tips or suggestions would be greatly appreciated.

  2. #2
    Registered User
    Join Date
    Nov 2001
    One solution is to NOT each bit, thus you will end up with the reverse integer.

    The NOT syntex for C++ is this: ~


  3. #3
    Cheesy Poofs! PJYelton's Avatar
    Join Date
    Sep 2002
    To get the last number in an int, just do a modulus 10. For example N%10 will give you the last digit for the number N. If you want to keep going, divide N by 10 to chop off the last number, then do modulus again.

  4. #4
    Registered User
    Join Date
    Aug 2001
    you could put the number in a char array, use a for loop or two to put the number backwards in another array, and then use atoi() to make it an integer again..

  5. #5
    Registered User
    Join Date
    Mar 2002
    South Africa
    Or you could read them into a stack (instead of a string/char*), just push each one in as you get to it. Then pop them out again.
    Something like this, where Str is an AnsiString that contains the string just inputed, and S is a stack:
      for (int i = 0; i < Str.Length(); i++)
      AnsiString Str2;
      for (int i = 0; i < Str.Length(); i++)
        Str2 = S.Pop(Str[i])

  6. #6
    Seeking motivation... endo's Avatar
    Join Date
    May 2002
    I think the char array idea is simplest, then just read the number as you would a word and process the array elements indivually in a loop
    Couldn't think of anything interesting, cool or funny - sorry.

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