Question

Modify the DemoSalesperson application so each Salesperson has a successive ID number from 111 through 120 and a sales value that ranges from $25,000 to $70,000, increasing by $5,000 for each successive Salesperson. Save the file as DemoSalesperson2.java.

Answer 1

Answer:

Here is the modified DemoSalesperson2

public class DemoSalesperson2{ // class DemoSalesperson2

public static void main(String[] args) { //start of main() function body

SalesPerson[] sp = new SalesPerson[10]; // creates an array of SalesPerson object named sp

int start_id =111; // assign 111 to starting id number

double start_sal=25000; //assign 25000 to starting salary means salary will start from amount 25000

 for (int i =0; i<sp.length; i++) { //loop iterates until the value of loop variable i remains less then length of the array object sp

  sp[i] =new SalesPerson(start_id+i,start_sal+5000*(i)); /*at each iteration  ID number from 111 through 120 and a sales value that ranges from $25,000 to $70,000, increasing by $5,000 for each successive is displayed using object array sp[] which calls the SalesPerson constructor to access id and sales */

 System.out.println(sp[i].getId()+"   "+sp[i].getAnnualSales() );  } } } /*uses object sp of class SalesPerson to access the methods getId which returns the id and getAnnualSales method which returns the annual sales, to display id and annual sales */

Explanation:

The question first requires a SalesPerson class with these requisites:

Class name: Salesperson.

Data fields for Salesperson: int ID number , double annual sales amount.

Methods: constructor SalesPerson() that requires values for both data fields, as well as get and set methods for each of the data fields.

So according to the complete question's requirement, I have implemented SalesPerson class:

public class SalesPerson {   // class name

//data members: integer type id variable and double type sales variable

   private int id;  

   private double sales;  

   public SalesPerson(int id_no, double annual_sales) {   //constructor that requires values for id and sales

       id = id_no;  

       sales = annual_sales;     }  

   public int getId() {   //accessor getId() method to get or access the value of id data field

       return id;     }  

   public void setId(int id_no) {   //mutator setId to set the value of id data field

       id = id_no;     }  

   public double getAnnualSales() {   //accessor getAnnualSales() method to get or access the value of sales data field

       return sales;     }  

   public void setAnnualSales(double annual_sales) { //mutator setAnnualSales to set the value of sales data field

       sales = annual_sales;     }  }

However you can use my DemoSalesperson2 application for your own SalesPerson class.

Now I will explain the working of for loop used in DemoSalesperson2

Iteration 1:

i=0

i<sp.length is true because length of sp[] is 10 so i<10

This means the body of for loop will execute.

The statement inside the body of for loop is :

 sp[i] =new SalesPerson(start_id+i,start_sal+5000*(i));

class SalesPerson constructor is used to access the data members of SalesPerson class

start_id = 111

start_sal=25000

start_id+i = 111 + 0 = 111

start_sal+5000*(i) = 25000 + 5000 (0) = 25000

The values 111 and 25000 are stored to sp[0] means at the first index of the sp array.

System.out.println(sp[i].getId()+"   "+sp[i].getAnnualSales() );  

This statement uses sp object to get access to the getId and getAnnualSales methods to print the id number and sales amount.

So the output at 1st iteration is:

111   25000.0

Iteration 1:

The value of i is incremented to 1 so now i = 1

i<sp.length is true because length of sp[] is 10 so i<10

This means the body of for loop will execute.

The statement inside the body of for loop is :

 sp[i] =new SalesPerson(start_id+i,start_sal+5000*(i));

class SalesPerson constructor is used to access the data members of SalesPerson class

start_id = 111

start_sal=25000

start_id+i = 111 + 1 = 112

start_sal+5000*(i) = 25000 + 5000 (1) = 25000 + 5000 = 30000

The values 111 and 25000 are stored to sp[1] means at the first index of the sp array.

System.out.println(sp[i].getId()+"   "+sp[i].getAnnualSales() );  

This statement uses sp object to get access to the getId and getAnnualSales methods to print the id number and sales amount.

So the output at 1st iteration is:

112   30000.0

The loop keeps iterating and the value of id is incremented by 1 and value of sales is increased by 5000 at every iteration.

This loop continues to execute until the value of i exceeds the length of sp array i.e. 10.

The values from iteration 1 to 8 following the above explanation are:

Iteration 1:

111    25000.0

Iteration 2:

112    30000.0

Iteration 3:

113    35000.0

Iteration 4:

114   40000.0  

Iteration 5:

115   45000.0  

Iteration 6:

116   50000.0                                                          

Iteration 7:

117   55000.0                                                                                                      

Iteration 8:                                                                                      

118   60000.0      

Iteration 9:                                                                                    

119   65000.0

Iteration 10:                                                                                    

120   70000.0

At iteration 11 the for loop body will not execute as value of i at 11th iteration is i = 10 and i<sp.length evaluates to false as i = sp.length because length of sp array is 10 and now the value of i is also 10. So the loop ends. Screenshot of the program and its output is attached.