# Simple Question(maybe)

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• 10-06-2004
CC4CocoaPuffs
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.
• 10-06-2004
Vicious
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.
• 10-06-2004
CC4CocoaPuffs
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)?
• 10-06-2004
Zach L.
Simple formula:
# of base b digits in n = floor(log{b}(n)) + 1 (where log{b}(n) means log base b of n)
• 10-06-2004
pablo615
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
• 10-06-2004
CC4CocoaPuffs
thanks all.
• 10-06-2004
jlou
Using a for loop along with the / operator might be more appropriate for learning.
• 10-07-2004
C++Child
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.....
• 10-07-2004
jlou
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.
• 10-07-2004
C++Child
Thank you jlou, I didn't know that. I usually append my strings with '\0' anyways.
• 10-07-2004
elad
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.