pre-written functions

Question 1

pre-written functions

Answer 1

defined in system libraries

contain return types, names, datatype parameters

Question 2

stdio.h

Answer 2

library with functions for performing input and output

printf()
scanf()

Question 3

stdlib.h

Answer 3

library with general functions

int rand() - returns random integers
int abs(int x) - returns absolute value of int x

Question 4

math.h

Answer 4

library with assortment of mathematical functions

double fabs(double x) - returns the absolute value of double x

Question 5

time.h

Answer 5

library with functions regarding dates and time

time(NULL) - returns time since Jan 1, 1970

Question 6

ctype.h

Answer 6

library with functions for mapping characters

int isalpha(int c) - checks if the character passed is alphabetic