条件语句 If-Else 中的逻辑错误 Java

Question

I have this given problem that is: A computer rental has a REGULAR CHARGE per hour for the first three hours or less. The excess of three hours would be charged by 10 percent less of the regular charge per hour. And my source code is:

    System.out.print("ENTER REGULAR CHARGE: ");
    int charge = scan.nextInt();
    
    System.out.print("ENTER REGULAR HOURS: ");
    int hours = scan.nextInt();
    
    scan.close();
    
    if (hours <= 3)
    {
        int bill= charge * hours;
        System.out.print("RENTAL BILL IS: " +bill);
    }
    else
    {
        double bill = (double) (charge * hours)-0.10;
        System.out.print("RENTAL BILL IS: " +bill);
    }

and the expected output should be:

ENTER REGULAR CHARGE: 4
ENTER REGULAR HOURS: 10
RENTAL BILL IS: 39

but my outcome goes:

ENTER REGULAR CHARGE: 4
ENTER REGULAR HOURS: 10
RENTAL BILL IS: 39.9

I don't know if there's a problem in my formula or the variable that I used. It would be very helpful if someone pointed out the errors in my source code.

Answer 1

You need to calculate price for 3 hours and deduct it from total hours in second condition. Also apply discount to the original price, multiply it to remaining hours, and add those hours price to 3-hour price.

The code is below

import java.util.Formatter;
import java.util.Scanner;
public class string{
public static void main(String[] args){
    
    double bill= 0;
    Scanner scan = new Scanner(System.in);
    
    System.out.print("ENTER REGULAR CHARGE: ");
    double charge = scan.nextInt();

    System.out.print("ENTER REGULAR HOURS: ");
    int hours = scan.nextInt();

    scan.close();
    
    if (hours <= 3){
        // calculation for 3 hours or less
        bill= charge * hours;
        System.out.print("RENTAL BILL IS: " +bill);
    }
    else {
        // subtracting 3 hours from total hours if hours are more                              
        int remainingHrs = hours - 3; 
        
        // calculating price for 3 hours to add to remaining hours price                                         
        double priceforthreeHours = charge * 3;
        
        // calculating discountedprice (10% discount)
        double discprice = charge - (charge * 0.10);
        
        // adding it all together 3hrs + discounted price                                                        
        bill = priceforthreeHours +(remainingHrs * discprice);
        
        System.out.print("RENTAL BILL IS: ");
        
        // formatting price using java.util.Formater
        System.out.printf(" %.2f, %n",bill); 
        
     
    }
}   

}