A char* is basically a pointer to a character. What C does is frequently makes this pointer point to the first character in an array.
An std::string is a class that is much like a vector. Internally, it handles the storage of an array of characters, and gives the user several member functions to manipulate said stored array as well as several overloaded operators.
Reasons to use a char* over an std::string:
C backwards-compatibility.
Performance (potentially).
char*s have lower-level access.
Reasons to use an std::string over a char*:
Much more intuitive to use.
Better searching, replacement, and manipulation functions.
Reduced risk of segmentation faults.
Example :
char* must be used in conjuction with either a char array, or with a dynamically allocated char array. After all, a pointer is worthless unless it actually points to something. This is mainly used in C programs:
char somebuffer[100] = "a string";
char* ptr = somebuffer; // ptr now points to somebuffer
cout << ptr; // prints "a string"
somebuffer[0] = 'b'; // change somebuffer
cout << ptr; // prints "b string"
notice that when you change 'somebuffer', 'ptr' also changes. This is because somebuffer is the actual string in this case. ptr just points/refers to it.
With std::string it's less weird:
std::string a = "a string";
std::string b = a;
cout << b; // prints "a string"
a[0] = 'b'; // change 'a'
cout << b; // prints "a string" (not "b string")
Here, you can see that changing 'a' does not affect 'b', because 'b' is the actual string.
But really, the major difference is that with char arrays, you are responsible for managing the memory, whereas std::string does it for you. In C++, there are very few reasons to use char arrays over strings. 99 times out of 100 you're better off with a string.
Until you fully understand memory management and pointers, just save yourself some headaches and use std::string.
std::stringever not accompanied by rationalization? – Impostume