Prata exs 7.7

//prata exc 7 chapter 7
//working, but i'm not happy about names vars and consts
//have to read a book about properly naming!
//another matter - which is better style -introducing after_tax or not?
#include <stdio.h>
#include <ctype.h>
#define H_RATE 10.0 //hourly rate
#define O_RATE 15.0 //overtime rate
#define TAX1 0.15
#define TAX2 0.2
#define TAX3 0.25
#define BREAK1 300.0
#define BREAK2 450.0
#define WEEK 40.0

int main()
{
    float hours,before_tax, after_tax, tax;
    printf("How many hours have you worked this week?\n");
    scanf("%f",&hours);

    //calculating salary before tax
    if(hours<=WEEK)
        before_tax = hours * H_RATE;
    else
        before_tax = WEEK*H_RATE +(hours-WEEK)*O_RATE;

    //calculating taxes
    if(before_tax<BREAK1)//if salary less than 300
    {
        tax = before_tax*TAX1;

    }
    else if(before_tax<BREAK2)//if salary less than 450
    {
        tax = BREAK1*TAX1+ (before_tax-BREAK1)*TAX2;

    }
    else //salary equal or over 450
        tax = BREAK1*TAX1 + (BREAK2-BREAK1)*TAX2+ (before_tax-BREAK2)*TAX3;

     after_tax = before_tax - tax;

     printf("before %f, after %f, tax %f",before_tax,after_tax,tax);


    return 0;
}