return 0 in converting string to integer

[ft95]

Hi.
I used atoi(string1.c_str()) for convertig a binary string to integer.
but it always return 0.
why?????!!!!1

[vlad from moscow]

What do you mean when saying "binary string"? atoi can only convert to int a representattion of an integer number writtten in decimal notation.

[ft95]

I mean that in this string we just have 0,1.

[Chervil]

It must be that the string was not a valid decimal number. What exactly was the string?

By the way, you can use strtol() to convert a string in any base from 2 to 36 into a long int.

http://www.cplusplus.com/reference/cstdlib/strtol/

[ft95]

I wrote like this:

string number;
cin>>number;
int value=atoi(number.c_str())

[Chervil]

Yes, but what does the string contain?

[vlad from moscow]

If 'number' does not represent an integer literal then of course you will not get a valid value.

[ft95]

it contains 1 and 0.

edit:
it can get a number between and including 0 and 9

[Chervil]

May I ask, 1 and 0 like this, "1 0" or " 0 1 " or "10" or what?

it can get a number

what is "it", please?

At any rate, atoi() should be able to handle any string which converts to a valid integer, usually in the range "-2147483648" to "[phone]". The string "10" certainly fits within that range.

As stated in the reference below, if the input is not a valid integer, the result is zero. http://www.cplusplus.com/reference/cstdlib/atoi/

[moorecm]

How about this?

int value;
cin >> value;

[Juan Camaney]

my problem is similar, I have to convert a string to int and strings.

For example, 123TCat and Dog W346 edf fedh are good

assign 123 to x
Cat and dog to str
346 to y
are good to line

[ft95]

usually in the range "-2147483648" to "[phone]"

ok,it was my problem.
number was out of this range!!
Thank you

[Chervil]

Well, that was hard work. I asked three times what was the exact string, and still got no answer. We would have reached the solution much faster if we worked together in cooperation.

[ft95]

ok,I'm sorry!!
Thank you again