The C standard library provides numerous built-in functions that your program can call. For example, strcat() to concatenate two strings, memcpy() to copy one memory location to another location, and many more functions. A function can also be referred as a method or a sub-routine or a procedure, etc.
Quick Answer. Authors use repetition for several reasons, including making a point, to set a rhythm, link topics or ideas and to make discussions easier to follow. Using repetition in writing is something that still has rules and should be used with some thought instead of randomly.
A variation or version. (computing) The use of repetition in a computer program, especially in the form of a loop. (computing) A single repetition of the code within such a repetitive process. The code calculates the appropriate value at each iteration.