Only C Language not C++

1. For each of the following functions, explain its purpose, the type(s) of its output parameters, and the type(s) of its input parameter(s). Also, indicate if it is user-defined or if it is from the string library or from the ctype library. (Marks 1.25*5=10)

strcpy

strncpy

strncat

islower

scanline

isalpha

strlen

strcmp