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const char* and std::string problem with .net (works with 6.0)
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anelma via .Net Guru (VIP)
Following code works fine, when compiled with VS 6.0, but not anymore when compiled in .NET. What's wrong here, I can't see it by myself?
arrString content will be garbage with .net compilation, but when compiled with 6.0 it contains string from Vector (that's how I want it to work).

std::vector<std::string> Vector;
...

void MyClass::DoThis(std::vector<std::string> Vector)
{
const char *arrString[10];
    
for (int i = 0; i < 10 && i < Vector.size(); i++)
arrString[i] = Vector[i].c_str();

When I debug these, I see that the problem is with my array of const char*. Const char* items seems to change, when std:string changes. For example,
Vector[0].c_str = "dog"
arrString[0]="dog"
Vector[1].c_str = "cat"
arrString[0]="cat" --> this is the problem, why it happens?
This happens only with .net, with 6.0 remains arrString[0] = "dog"    

--------------------------------
From: anelma

-----------------------
Posted by a user from .Net Guru (http://www.dot-net-guru.com/)

<Id>FCPH9ioddE2faW+WEvjukQ==</Id>
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Vladimir Nesterovsky
"anelma via .Net Guru" <Click here to reveal e-mail address> wrote in message
news:Click here to reveal e-mail address...
> Following code works fine, when compiled with VS 6.0, but not anymore when
compiled in .NET. What's wrong here, I can't see it by myself?
> arrString content will be garbage with .net compilation, but when compiled
with 6.0 it contains string from Vector (that's how I want it to work).
[Original message clipped]

example,
[Original message clipped]

std::string owns memory returned with c_str(). Destiny of this memory is
implementation defined when string is changed.
--
Vladimir Nesterovsky
e-mail: Click here to reveal e-mail address
home: www.nesterovsky-bros.com
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Ary Sulistyono
Using VS.Net 2003, I don't see the problem you're seeing.

void
MyChass::DoSomething(vector<string> v)
{
    const char *arr[10];
    for (int i = 0; i < 10 && i < v.size(); i++)
    {
        arr[i] = v[i].c_str();
    }

    // this will print "dog" and "cat" correctly
    for (int j=0; j < 10 && j < v.size(); j++)
    {
        cout << "arr[" << j << "] = " << arr[j] << endl;
    }
}

int _tmain(int argc, _TCHAR* argv[])
{
    MyChass m;
    std::string s1 = "dog";
    std::string s2 = "cat";
    std::vector<std::string> v;
    v.push_back(s1);
    v.push_back(s2);
    m.DoSomething(v);
    return 0;
}

Ary Sulistyono

anelma via .Net Guru wrote:
[Original message clipped]
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