Question

(Java)

Rewrite the following exercise below to read inputs from a file and write the output of your program in a text file.

• Ask the user to enter the input filename. Use try-catch when reading the file.
• Ask the user to enter a text file name to write the output in it. You may use the try-with-resources syntax.

An example to get an idea but you need to have your own design:

try (
      // Create input files
      Scanner input = new Scanner(sourceFile);
      
    ) {        
      while (input.hasNext()) {
        String s1 = input.nextLine();        
      }

try (
      // Create output files      
      PrintWriter output = new PrintWriter(targetFile);
    ) {        
              
        output.println(s2);
      }

or try {

}
catch (IOException ex) {
      System.out.println("IO Errors! Can not find the file to read!");
}

and...

Rewrite the following exercise to check the user inputs to be:

• double

and

• positive

with using try-catch (and/or throw Exception )

The exercise: Write a program to prompt the user for hours and rate per hour to compute gross pay. Calculate your pay computation to give the employee 1.5 times the hourly rate for hours worked above 40 hours.

Your code should have at least the following methods to calculate the pay. (VOID and NON-STATIC)

1. getInputs
2. calculatePay
3. printPay

Create an object of the class and declare the method as the instance methods.

Enter Hours: 45

Enter Rate: 10

Pay: 475.0

475 = 40 * 10 + 5 * 10*1.5

• Put at least two outputs (two different numbers and results)  (results after you run your code) at the end of your code as a multi-line comment.

/*

Your result

*/

Answer 1

Below is the solution:

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Scanner;

public class ReadWritePayRateCalculate {
   // declare the variable
   static double hours = 0;
   static double rate = 0;
   static double pay = 0;
   static Scanner in = new Scanner(System.in); // scanner class

   public static void main(String[] args) throws IOException {
       String fileName, targetFile; // declare variable
       try {
           System.out.print("Please enter a file name:"); // ask to enter a file name
           fileName = in.nextLine(); // read a file name
           File sourceFfile = new File(fileName); // read a input file name
           Scanner input = new Scanner(sourceFfile); // scanner input
           while (input.hasNextLine()) { // read file of each line
               String s1 = input.nextLine(); // store each line in s1 string
               System.out.println(s1); // print each line of s1
           }
           input.close(); // close the file
       } catch (Exception e) { // Error
           e.printStackTrace(); // error if not file found
       }

       try {
           System.out.println("\nPlease enter the the file name: "); // ask to append the text to the file
           targetFile = in.nextLine(); // input string read from keyboard
           // Create output files
           PrintWriter output = new PrintWriter(targetFile);
           // write into file
           output.println("This the first line write to file");
           output.println("This the second line write to file");
           output.println("File write done!");
           output.close(); // close the file
       } catch (IOException e) { // Error
           System.out.println("IO Errors! Can not find the file to read!");
       }

       // pay rate calculate
       getInputs(in, hours, rate); // get the input
       calculatePay(); // calculate the pay rate
       printPay(); // print the pay

   }

   // get input
   public static void getInputs(Scanner in, double h, double r) {
       while (true) {
           try {
               System.out.print("Enter Hours: "); // ask to enter hours
               hours = Double.parseDouble(in.next());
               break; // will only get to here if input was a double
           } catch (NumberFormatException e) {
               System.out.println("Invalid input");
           }
       }

       while (true) {
           try {
               System.out.print("Enter Rate: "); // ask to enter rate
               rate = Double.parseDouble(in.next());
               break; // will only get to here if input was a double
           } catch (NumberFormatException e) {
               System.out.println("Invalid input");
           }
       }
   }

   // calculate pay
   public static void calculatePay() {
       // check for the hours > 40
       if (hours > 40) {
           pay = (40 * rate) + (hours - 40) * 1.5 * rate; // calculate overtime 40 hours
       } else
           pay = hours * rate;
   }

   // print pay
   public static void printPay() {
       System.out.println("Pay: " + pay);
   }
}

sample output:

Please enter a file name:student.txt
1. John m 18
2. William m 22
3. Susan f 21
4. Jack m 19
5. Jennifer f 18
6. Sophia f 21

Please enter the the file name:
student1.txt
Enter Hours: a50
Invalid input
Enter Hours: 45
Enter Rate: a4
Invalid input
Enter Rate: 10
Pay: 475.0