Question $5(20$ marks$)$

A program written to calculate the mean of three input data from the user which is listed as below:

$```$

#include

void main$($void$)$

$\{$ float value$0,$ value$1,$ value$2,$ total $=0,$ mean;

printf $("$This program takes in three data $")$;

printf $("$and calculate the mean.

$")$; $//$Introduction

printf $("$Enter data no$.1$ : $")$; $//$Prompt user

scanf $("*/$f$",$ &value$0)$; $//$Get the first data

total $=$ total $+$ value$0$; $//$Obtain the total

printf $("$Enter data no$.2$ : $")$; $//$Prompt user

scanf $("\%$f$",$ &value$1)$; $//$Get the second data

total $=$ total $+$ valuel; $//$Obtain the total

printf $("$Enter data no$.3$ : $")$; $//$Prompt user

scanf $("\%$f$",$ &value$2)$; $//$Get the third data

total $=$ total $+$ value$2$; $//$Obtain the total

mean $=$ total $/3\mathrm{.}0$; $//$Calculate the mean

printf $("$The mean is $\%$f

$",$ mean$)$;

$\}//$End of program

$```$

Program $3$

Analyze Program $3$ in detail and answer the following questions:

$($a$)($i$)$ State the data type used by all the variables in Program $3.$

$[2$ marks$]$

$($ii$)$ Explain two drawbacks of the method used in Program $3$ to collect data.

$($iii$)$ Explain the purpose of initializing the variable total.

$($b$)$ Modify Program $3$ to take in any number of input data and calculate the mean from the input data.

$-$ Use array to store the input data.

$-$ The number of input data is determined by the user, with maximum up to $1000$ data.

$-$ Use the preprocessor directive: $\backslash$#define to set the maximum number of input data at $1000.$

$-$ The program needs to check whether the number of input data keyed in by the user exceeds the maximum allowable size or not, which is $1000.$ Write a function for this purpose, which can be called from the main function.

$-$ Use loop to repeatedly collect the input data from the user and store them in the array.