What does it mean by null in programming?

Write a program that uses a two-dimensional array to store the highest and lowest temperatures for each month of the year. the program should output the average high, average low, and the highest and lowest temper- atures for the year. your program must consist of the following functions: a. function getdata: this function reads and stores data in the two- dimensional array. b. function averagehigh: this function calculates and returns the average high temperature for the year. c. function averagelow: this function calculates and returns the aver- age low temperature for the year. d. function indexhightemp: this function returns the index of the highest high temperature in the array. e. function indexlowtemp: this function retur