There are two common ways of treating the string data type, either as a fundamental type or as a class. Programming languages generally use one representation or the other. C++ is somewhat unique in that it uses both. It inherits C-strings, a fundamental or primitive string representation based on character arrays and character pointers, from the C-programming language. But C++ also includes a full-featured string class that is very similar to Java's String class.
Know
C-strings
How to define a C-string variable
The relation between a C-string, a char array, and a character pointer
What makes a character array into a C-string (know about the null-termination character)
How to read C-strings containing spaces: the C-string getline function
How to access the individual characters in a string: the index operator []
The correct header file to access the C-string functions, <cstring>, and when it is needed
How to find the length of a C-string (know strlen function)
How to track the capacity of a C-string (sometimes you must look at the context to tell if "size" refers to "length" or "capacity")
That you CANNOT use .length() with a C-string
How to copy, concatenate, and test two C-strings for equality: stcpy, strcat, and strcmp
How to pass C-strings to functions
How to return C-strings from functions (use caution when returning local C-string variables)
How to access and use command line arguments in a C++ program: void main(int argc, char* argv[])
strings
How to define a string variable
The correct header file to access the string functions, <string>, and when it is needed
How to read strings containing spaces: (know about the string getline function)
How to access the individual characters in a string: the index operator [] and the at function
How to find the length of a string (know the length and size member functions)
How to find the capacity of a string (know the capacity member function)
How to copy, concatenate, and test test two string objects for equality: the string operators =, +=, +, ==, and !=
The string relational operators: <, ≤, >, and ≥
How to convert a string object to a number and a number to a string object