std::string to char*?

Question

I want to convert a **std::string** into a **char*** or **char[]** data type. std::string str = "string"; char* chr = str; Results in: **“error: cannot convert ‘std::string’ to ‘char’ ...”**. What methods are there available to do this?

Answer 1

We can get access to the underlying C string

using std::string's c_str() method, but we cannot change the string.

Like so:

#include <iostream>

int main(int argc, const char* argv[]) {

std::string s = "Standard string";

const char* p = s.c_str(); // this gives access to the C string

while (*p != '\0') {

std::cout << (char)toupper(*p++) << " "; // string not changed

}

std::cout << "\nThat's all\n";

return 0;

}

//----------- OUTPUT ------------------------------

S T A N D A R D S T R I N G

That's all

Program ended with exit code: 0

If we wanted to manipulate the underlying C string, and then create a new std::string, we would have to duplicate or copy the underlying C string to a new buffer, then construct a new std::string from the modified C string.

Hope that helps.