Problem $5$: Problem $5$: Write a program to calculate a discount based on the quantity and the price of each item of purchasing. The program prompts the user to insert the positive purchased number of items $($num should be positive$)$ and the price of each item. The program calculates the price after discount as follows:

discount$(num)=\{\begin{array}{ccc}& no\text{c}\text{h}\text{a}\text{n}\text{g}\text{e}\text{,}\text{n}\text{u}\text{m}& <mn\; id="EditorElement\_203984">1</mn><mn\; id="EditorElement\_203985">0</mn>\\ & \text{n}\text{o}\text{r}\text{m}\text{a}\text{l}\text{p}\text{r}\text{i}\text{c}\text{e}**0\mathrm{.}2,10\text{n}\text{u}\text{m}& 20\\ & \text{n}\text{o}\text{r}\text{m}\text{a}\text{l}\text{p}\text{r}\text{i}\text{c}\text{e}**0\mathrm{.}3,20<mtext\; id="EditorElement\_204092"></mtext><mtext\; id="EditorElement\_204093">n</mtext><mtext\; id="EditorElement\_204095">u</mtext><mtext\; id="EditorElement\_204097">m</mtext><mtext\; id="EditorElement\_204099"></mtext>& 50\\ & \text{n}\text{o}\text{r}\text{m}\text{a}\text{l}\text{p}\text{r}\text{i}\text{c}\text{e}**0\mathrm{.}4,50<mtext\; id="EditorElement\_204151"></mtext><mtext\; id="EditorElement\_204152">n</mtext><mtext\; id="EditorElement\_204154">u</mtext><mtext\; id="EditorElement\_204156">m</mtext><mtext\; id="EditorElement\_204158"></mtext>& 100\\ & \text{n}\text{o}\text{r}\text{m}\text{a}\text{l}\text{p}\text{r}\text{i}\text{c}\text{e}**0\mathrm{.}5,\text{n}\text{u}\text{m}& >100\end{array}$

Input $/$Output Samples:

Bnter quantity of purchasing: $-2$ Invalid quantity

Enter the quantity of purchasing: $10$

Enter the price of each item: $30$

You have bought $10$ peices

The normal price is $300$

The price after discount is:$240$

$..$ Program finished with exit code $0$

Press ENTER to exit console.

I need answer with c$++$