C provides many built-in functions in addition to the printf(), scanf(), and strcpy() functions you have seen so far throughout the book. These built-in functions increase your productivity and save you programming time. You don't need to write as much code because the built-in functions perform many useful tasks for you.
This chapter teaches you the following topics:
Character conversion functions
Character and string testing functions
String manipulation functions
String I/O functions
Mathematic, trigonometric, and logarithmic functions
