The name of each of these C++ headers is of the form cname, where name is the string that results when the “.h” extension is removed from the name of the equivalent C Standard Library header. For example, the header files <stdlib.h> and <cstdlib> are both provided by the C++ Standard Library and are equivalent in function, with the exception that all declarations in <cstdlib> are located within the std namespace.

Provides string object and functions including size, length, append, insert, replace, copy, find, substr, compare, push_back and more.

Provides string manipulation functions including strcpy, strncpy, strcat, strncat, strcmp, strncmp and more.

Provides cin, cout and cerr commands.

Provides file handling functions including open, is_open, close, gcount, getline, ignore, peek, read, put, write, flush and more.

• cstdlib here is used to provide the srand and rand commands.
• ctime provides the time function.
  

Provides many functions such as atof, atoi, atol, calloc, free, malloc, realloc, exit, div and more.

Provides character transformation functions including toupper, tolower, widen, narrow.