Simple Question(maybe)

This is a discussion on Simple Question(maybe) within the C++ Programming forums, part of the General Programming Boards category; Im doing a small thing for school, and i want to make a program to have you enter a number, ...

  1. #1
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    Simple Question(maybe)

    Im doing a small thing for school, and i want to make a program to have you enter a number, and have it count the digits, and then tell you how many digits there are.

    I only know a little C++, and would like to know how to go about haveing it count the digits. thanks for anyone who helps.

  2. #2
    i dont know Vicious's Avatar
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    Hmm you could either input the numbers in a string and find the strings length. Or you could do a little checking.

    like if its less than 10 then its 1 digit... less the 100 and greater than or equal to 10 then 2 digits.
    What is C++?

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    The first idea is what i was thinking i believe, because if i did the second one, its almost an infinite list.

    Now how would i go about doing that. Quick example (anyone)?
    Last edited by CC4CocoaPuffs; 10-06-2004 at 05:19 PM.

  4. #4
    Toaster Zach L.'s Avatar
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    Simple formula:
    # of base b digits in n = floor(log{b}(n)) + 1 (where log{b}(n) means log base b of n)
    The word rap as it applies to music is the result of a peculiar phonological rule which has stripped the word of its initial voiceless velar stop.

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    It can't be an infinite list because the variables are only able to hold a number so large... But the string route is a good approach. try sprintf, that'll get you what you want.

    PK

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    thanks all.

  7. #7
    Registered User jlou's Avatar
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    Using a for loop along with the / operator might be more appropriate for learning.

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    If you include the header file <string>, you can make a string using the variable type std::string; and if you include the header file <cstring>, you can find the length of a string using the strlen(name_of_std::string_var) if that is helpful.....
    Child who knows C++
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  9. #9
    Registered User jlou's Avatar
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    C++Child, you can find the length of a std::string using its length() or size() function, and you don't need <cstring> to do that.
    Code:
    std::string name_of_stdstring_var("fifteen letters");
    int fifteen = name_of_stdstring_var.length();
    The strlen function in <cstring> applies to C-style, null terminated character arrays, not std::string.

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    Thank you jlou, I didn't know that. I usually append my strings with '\0' anyways.
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  11. #11
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    STL strings are null terminated as well. Under the hood STL strings have the same null terminated char array as in a C style strings, they are just hidden behind an interface that makes them easiert to be manipulated.

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