Please do in C$++$

The program below is about a clothing company that sold T$-$shirts for $$19\mathrm{.}50$ each. Quantity discounts

are given to the first $70$ customers.

$($Total $60$ points$)$

#include

using namespace std;

int main $()\{$

int quantity;

double purchaseAmount, finalAmountPaid ;

for $($ int count $=1$; count ; count $++)\{$

cout ln Enter quantity: $"$;

cin $\backslash$gg$>$ quantity;

purchaseAmount $=$ quantity $*19\mathrm{.}50$;

discountAmount $=$ purchaseAmount $*0\mathrm{.}20$;

finalAmountPaid $=$ purchaseAmount $-$ discountAmount;

$\}$

$//20\%$ discount

You are going to modify and rewrite the main function on pages $3$ and $4.$ Follow carefully the

instructions, if you want to get full credit. $(15$ points$)$

Step#$1$: $($replace line $1)$ Replace the for loop with a while loop. $(5$ points$)$

Step#$2$: Replace lines $2$ and $3.$ Call the function" inputQuantity to input the quantity. Description of the

function: "inputQuantity" will read one integer, validate it with a loop $($quantity must be a positive

number$)$ and return it to the main function. $(10$ points$)$

Step#$3$: Replace line $4.$ Call the function "calculatePurchaseAmount" to calculate the purchase amount.

Description of the function: "calculatePurchaseAmount" will receive $2$ parameters: the

quantity and the T$-$shirt price. It will multiply the quantity times the T$-$shirt price and it will return

it to the main function $(10$ points$)$

Write the function on page $5.$

Step#$4$: Replace line $5.$ Call the function "calculateDiscount" to calculate the discount amount.

Description of the function: "calculateDiscount" will receive $2$ parameters: the quantity and the

Return the discount amount.

Write the function on page $6.$

$(10$ points$)$

$($do not change line $6)$ that calculates the finalAmountPaid

Step#$5$: Calculate the average finalAmountPaid. $($Hint: accumulate all finalAmountPaid and

divide by the number of customers$)(10$ points$)$