C :: Read Amount Of Order From Standard Input / Compute And Print Total Price After Discount

A Bookseller makes special discount for multiple orders of a book as follows:

AMOUNT and DISCOUNT as follows.

5-9 5% 10-14 10% 15-19 15% 20+ 20%

Write a C main function to read the amount of order from the standard input and compute and print the total price of the given order after the discount. Assume that unit price of a book is 10.00$

My problem is that.When i start with this

Code:
#include<stdio.h>
#include <stdlib.h>
int main(void)
{
int number;
float TotalPrice;
printf("enter a number:");

[Code] ....

I get 0 if i enter a number between 0 and 4(0 and 4 included). I don't know where I am doing a mistake. I also want to know if i can handle this buy just if statements. or how can i do it by while and for loops ?