Question

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how to copy char * into a string and vice-versa

I have to pass a value into a method that required a char *

MyMethod(char * parameter)
{
    // code
}

However, the parameter I need to feed it is currently a std::string. How do I convert the std::string to a char *?

std::string myStringParameter = //whatever

char * myCharParameter = //Convert here somehow

MyMethod(myCharParameter);

Answer 1

You are looking for the c_str() method:

char * myCharParameter = myStringParameter.c_str();

You might need to const_cast the return to get it into a char * instead of a const char *. Refrain from modifying the string though; it is the internal buffer of the std::string object. If you actually need to modify the string, you should use strncpy to copy it to another buffer:

char * myCharParameter = new char[myStringParameter.length() + 1];
strncpy(myCharParameter, myStringParameter.c_str(), myStringParameter.length() + 1);

// And later...
myStringParameter.assign(myCharParameter);
delete [] myCharParameter;