C / C++ / MFC

3-Sep-08 5:54

Hey all,

I've got this really annoying problem I just can't solve - I'm trying to print the elements of my array of strings, but I can't make it, I've tried several different ways.

Here's my code, which won't compile:

#include "stdafx.h"
#include <iostream>
using namespace std;

int main()
{
	string a[]={"a", "b", "c", "d", "e"};
	cout << a[3];
	return 0;
}</iostream>

I've been googling around for quite a while now and this code looks so right to me.

And one other thing; how can i create a string from several elements of this array?

Thx

/Joplinazz

toxcct3-Sep-08 6:05

3-Sep-08 6:05

why doesn't it compile ?

any compiler/linker errors ?

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Joplinazz3-Sep-08 6:11

3-Sep-08 6:11

Well, here's the huge description of the error I'm getting:

c:\andreas\programmering\cpp\arraytesting\arraytesting\arraytesting.cpp(11) : error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'std::string' (or there is no acceptable conversion)
        c:\program\microsoft visual studio 9.0\vc\include\ostream(653): could be 'std::basic_ostream<_Elem,_Traits> &std::operator <<<char,std::char_traits><char>>(std::basic_ostream<_Elem,_Traits> &,const char *)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(700): or       'std::basic_ostream<_Elem,_Traits> &std::operator <<<char,std::char_traits><char>>(std::basic_ostream<_Elem,_Traits> &,char)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(738): or       'std::basic_ostream<_Elem,_Traits> &std::operator <<<std::char_traits xmlns:std="#unknown"><char>>(std::basic_ostream<_Elem,_Traits> &,const char *)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(785): or       'std::basic_ostream<_Elem,_Traits> &std::operator <<<std::char_traits><char>>(std::basic_ostream<_Elem,_Traits> &,char)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(909): or       'std::basic_ostream<_Elem,_Traits> &std::operator <<<std::char_traits><char>>(std::basic_ostream<_Elem,_Traits> &,const signed char *)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(916): or       'std::basic_ostream<_Elem,_Traits> &std::operator <<<std::char_traits><char>>(std::basic_ostream<_Elem,_Traits> &,signed char)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(923): or       'std::basic_ostream<_Elem,_Traits> &std::operator <<<std::char_traits><char>>(std::basic_ostream<_Elem,_Traits> &,const unsigned char *)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(930): or       'std::basic_ostream<_Elem,_Traits> &std::operator <<<std::char_traits><char>>(std::basic_ostream<_Elem,_Traits> &,unsigned char)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(170): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::basic_ostream<_Elem,_Traits> &(__cdecl *)(std::basic_ostream<_Elem,_Traits> &))'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(176): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::basic_ios<_Elem,_Traits> &(__cdecl *)(std::basic_ios<_Elem,_Traits> &))'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(183): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::ios_base &(__cdecl *)(std::ios_base &))'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(190): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::_Bool)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(210): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(short)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(243): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(unsigned short)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(263): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(__w64 int)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(288): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(__w64 unsigned int)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(308): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(long)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(328): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(__w64 unsigned long)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(349): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(__int64)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(369): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(unsigned __int64)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(390): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(float)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(410): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(double)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(430): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(long double)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(450): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(const void *)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\program\microsoft visual studio 9.0\vc\include\ostream(470): or       'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::basic_streambuf<_Elem,_Traits> *)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        while trying to match the argument list '(std::ostream, std::string)'
Build log was saved at "file://c:\Andreas\Programmering\Cpp\ArrayTesting\ArrayTesting\Debug\BuildLog.htm"
ArrayTesting - 1 error(s), 0 warning(s)
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped
</char></char></char></char></char></char></char></char></char></char></char></char></char></char></char></char></char></char></char></std::char_traits></char></char></std::char_traits></char></char></std::char_traits></char></char></std::char_traits></char></char></std::char_traits></char></char></std::char_traits></char></char></char></char>

I'm using Visual C++ 2008.

/Joplinazz

toxcct3-Sep-08 6:24

3-Sep-08 6:24

Damn, only few errors would have suffice !!!
moreover, your lines are too long to fix the <pre> tag...

did you correctly included the header needed ?

#include <string>
#include <iostream>

also, try to use std::string::c_str() to print the string out:

cout << (a[3]).c_str();

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Joplinazz3-Sep-08 6:38

3-Sep-08 6:38

Haha, yeah you're right..

Thanks a lot for your help, the headers were the problem.
I didn't use #include <string> - Strange error(to me, hehe).

/Joplinazz

Roger Stoltz3-Sep-08 6:31

Roger Stoltz

3-Sep-08 6:31

Well, looks good to me.
I suppose you have included iostream. It doesn't show since you haven't used the small < and > wonders below the text input frame when you posted your message.

Joplinazz wrote:
And one other thing; how can i create a string from several elements of this array?

Try this:

#include <sstream>

int main()
{
    std::string Strings[] = { "a", "b", "c" };
    std::ostringstream stm;

    stm << Strings[2] << Strings[0] << Strings[1] << std::endl;
    std::cout << stm.str().c_str();
}

You'll get "cab" written to cout.

"It's supposed to be hard, otherwise anybody could do it!" - selfquote
"High speed never compensates for wrong direction!" - unknown

Joplinazz3-Sep-08 8:03

Creating a UI thread with CWinThread

3-Sep-08 8:03

Thanks Roger, I managed to make it work this way:

myString = a[0] + a[1];

/Joplinazz

sashoalm3-Sep-08 4:57

sashoalm

3-Sep-08 4:57

How do I create a UI thread capable of showing CDialog? I'm currently using AfxBeginThread for my working thread but also want to be able to display things like CDialog.DoModal from inside the worker thread. Do I have to make it a UI thread? How do I go about it?

There is sufficient light for those who desire to see, and there is sufficient darkness for those of a contrary disposition.
Blaise Pascal

Mark Salsbery3-Sep-08 5:06

Mark Salsbery

3-Sep-08 5:06

There's two versions of AfxBeginThread[^].

One creates a worker thread, the other creates a UI thread.

Multithreading: Creating User-Interface Threads[^]

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

sashoalm3-Sep-08 5:10

sashoalm

3-Sep-08 5:10

The second version wants a subclassed CWinThread, but I'm not sure where exactly to place my code in it. May be in InitInstance. Any suggestions?

I already have the worker thread and the code for it, I need to know what to change to make showing modal CDialogs possible.

There is sufficient light for those who desire to see, and there is sufficient darkness for those of a contrary disposition.
Blaise Pascal

Mark Salsbery3-Sep-08 5:20

Mark Salsbery

3-Sep-08 5:20

The second link shows common CWinThread overrides
and what those overrides should do.

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

sashoalm3-Sep-08 5:26

sashoalm

3-Sep-08 5:26

Sorry, I didn't notice it. Thanks.

There is sufficient light for those who desire to see, and there is sufficient darkness for those of a contrary disposition.
Blaise Pascal

ifstream

FrankMookie3-Sep-08 4:36

FrankMookie

3-Sep-08 4:36

Hi.I'm using visual c++ 9.0.
I want to do something like this:

string name = get_name();
string filename = name+("text.dat");

ifstream infile_file;

infile_file.open(filename);
(code)
(...)

I'm doing something wrong... or I am missing something.
Here is the error:
error C2664: 'void std::basic_ifstream<_Elem,_Traits>::open(const wchar_t *,std::ios_base::openmode,int)' : cannot convert parameter 1 from 'std::string' to 'const wchar_t *'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called
Thanks.

"Failure is always an option."

Re: ifstream [modified]

toxcct3-Sep-08 4:52

3-Sep-08 4:52

this is because you're building your appblication in UNICODE most probably...

~~try removing the declaration of that macro and rebuild.~~

forget that. std::string::c_str() is the way to go

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modified on Wednesday, September 3, 2008 11:05 AM

FrankMookie3-Sep-08 5:05

FrankMookie

3-Sep-08 5:05

I did remove the declaration in progect properties.. but didn't work...
But thanks anyway for your help.

"Failure is always an option."

toxcct3-Sep-08 5:06

3-Sep-08 5:06

yeah, after reading David's Answer, I figured out my mistake...

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David Crow3-Sep-08 4:57

David Crow

3-Sep-08 4:57

FrankMookie wrote:
infile_file.open(filename);

Try:

infile_file.open(filename.c_str());

"Love people and use things, not love things and use people." - Unknown

"The brick walls are there for a reason...to stop the people who don't want it badly enough." - Randy Pausch