string to char* and dynamic allocation???

[Zingam]

Sorry for this noob question but I'm very uncertain what I'm doing here. I have this function to convert a std::string to char*

char* stringToCharArray(std::string *stringParam)
{
    int stringLength = stringParam->length();
    char *stringTemp = (char*)malloc(stringLength*8 + 1);
    memcpy(stringTemp, stringParam->c_str(), stringLength);
    stringTemp[stringLength] = '\0';
    return stringTemp;
}

Then I use it like that:

    std::string company;
    company = string("BRB");
    quote->symbol = stringToCharArray(&company);

So if I later want to change the value of "company" to something else:

    company = "TRT";
    quote->symbol = stringToCharArray(&company);

This code is obviously wrong. Should I "free" quote->symbol before each assignment?
What is the proper way to convert a string to char* pass the result to a variable and later reuse that variable as many times as needed?

[coder777]

Why do you think that you need to convert string to char*?

[Galik]

You shouldn't generally use malloc() in C++, usually you use new[]. Also, cor copying c-strings there is strcpy() rather than memcpy():

char* stringToCharArray(std::string *stringParam)
{
    int stringLength = stringParam->length();

    // char *stringTemp = (char*)malloc(stringLength*8 + 1);
    char *stringTemp = new char[stringParam->length() + 1];

    // memcpy(stringTemp, stringParam->c_str(), stringLength);
    // stringTemp[stringLength] = '\0';
    strcpy(stringTemp, stringParam->c_str());

    return stringTemp;
}

EDIT:

Oh and yes, you need to delete[] quote->symbol before re-assigning it.

[Zingam]

1. Well, the compiler thinks it needs it. It's not me.

2. Thank you for the tips, Galik.

[Computergeek01]

Addressing the first element of a std::string by reference will treat it as a char*. So

std::string MyWord = "MyWord";
&MyWord[0]; //Treates The String As A char* 

[hanst99]

Why do any of that?
myString.c_str(); //get const char*

But really... what do you need it for?

[Zingam]

I am trying to use gSoap and it needs that.

[Disch]

+1 @ hanst. Just use the c_str function.

[Zingam]

OK. But is it safe to assign const char* to char*? I've read that it is not.

[Disch]

ah, you're right, it's not. Well it depends.

It's actually hard to say whether or not it would be appropriate here without knowing what you're doing. What gSoap is doing with this string would determine a lot of what you'd need to do here.