What is use of c_str function In c++

Question

I have just started reading C++ and found c++ having rich functions for string manipulation which C does not have. I am reading these function and came across c_str()<

Answer 1

Oh must add my own pick here, you will use this when you encode/decode some string obj you transfer between two programs.

Lets say you use base64encode some array in python, and then you want to decode that into c++. Once you have the string you decode from base64decode in c++. In order to get it back to array of float, all you need to do here is

float arr[1024];
memcpy(arr, ur_string.c_str(), sizeof(float) * 1024);

This is pretty common use I suppose.