stoi() CodeBlocks not working

Question

I am using codeblocks and i can't make stoi() function work. I read other questions regarding this issue but I couldn't solve it. I checked C+11, I am using namespace std and I have the string header. I don't know how can I solve this problem.

error: 'stoi' was not declared in this scope

Please add an [MCVE](http://stackoverflow.com/help/mcve), and describe your exact difficulty. — Deduplicator, Apr 14 '14 at 14:45
If this is what I think it is, it was fixed in newer versions of MinGW. Try http://sourceforge.net/projects/mingwbuilds/ — chris, Apr 14 '14 at 14:45
I installed the version you linked but it is still giving the same error @chris — user3526673, Apr 14 '14 at 14:55
Well, there's always this: http://tehsausage.com/mingw-to-string — chris, Apr 14 '14 at 15:15
Perhaps this is a dupe then: http://stackoverflow.com/questions/16132176/problems-with-stdstoi-not-working-on-mingw-gcc-4-7-2?rq=1 — chris, Apr 14 '14 at 15:36
It's always good to have questions that help people find other questions. — chris, Apr 14 '14 at 16:12

score 1 · Answer 1 · edited May 23 '17 at 12:16

found the answer on almost the same question here:

"It seems your MinGW needs a patch: Enabling string conversion functions in MinGW"

From this link you can download a .zip, than follow the instructions.

This patch enables the following list of C++11 functions and templates in the std namespace:
stoi, stol, stoul, stoll, stof, stod, stold, to_string, to_wstring

Attention, maybe you will haver errors with later versions, after using the copy/paste:

As Conduit said here:

"People should note that direct replacement of the files is not guaranteed to be safe on versions later than MinGW GCC 4.7 - use the pastebin snippets, open the files, and comment/add to the existing files. Applied as such, this still works fine on MinGW GCC 4.8.1 afai"

score 0 · Answer 2 · answered Apr 14 '14 at 14:55

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I would use atoi on the str.data() returned value, since it is supported in all compiler versions.

answered Apr 14 '14 at 14:55

George Nechifor

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atoi gave me another error. Because my string is not null terminated it doesnt work. – user3526673 Apr 14 '14 at 14:58
How about `str.c_str()` ? This should be guaranteed to be null terminated. – George Nechifor Apr 14 '14 at 15:02
`str.data()` is also guaranteed to be null-terminated. – chris Apr 14 '14 at 15:14
I could make it work with data(), thanks. But i would like to make stoi() work too if it is possible. – user3526673 Apr 14 '14 at 15:23

Deduplicator · Answer 3 · 2014-04-14T15:19:11.720

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Use

#include <string>

That should work. For reference: C++11 standard plus minor editorial changes.

Or perhaps you are forgetting to prefix with std::?

A workaround is calling .c_str() and using the <cstdlib> or <stdlib.h> functions.

edited Apr 14 '14 at 15:19

answered Apr 14 '14 at 15:02

Deduplicator

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I am already using that. That is why i dont understand the problem. I did everything i see from other posts and still not working. – user3526673 Apr 14 '14 at 15:04
In that case, can you just search in the header file? If needed make an file including only `` and search in the preprocessor output. – Deduplicator Apr 14 '14 at 15:06
Sorry, im pretty new to these stuff so what exactly should i do? I found the string.h file but i didnt understand a thing. @Deduplicator – user3526673 Apr 14 '14 at 15:13
@user3526673: First, ``and `` are different header files with different content. You really want the one without extension. Probably in the same directory though. Then serch for the prototype of `stoi()`. Anyway, first check if you used the right namespace. – Deduplicator Apr 14 '14 at 15:17
I am looking at include files in MinGW folder and all the files are header files with the little "h" icon on them. Its name was actually "string" but i said string.h because it was a header file. There are no other string in the header folder – user3526673 Apr 14 '14 at 15:31
By the way, for C++11, there's [N3485](http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3485.pdf), if you'd appreciate a later version. – chris Apr 14 '14 at 15:31
@chris: What else all is in there? – Deduplicator Apr 14 '14 at 15:35
@Deduplicator, No clue to be honest. 4 pages of stuff by the looks of it :p – chris Apr 14 '14 at 15:37

stoi() CodeBlocks not working

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