Question

We are to make a program about a car dealership using arrays. I got the code to display all cars in a list, so I'm good with that. What I'm stuck at is how to make it so when a user inputs s for search, it allows them to search the vehicle. Here is what I have so far

    public class Car {

        String color;
        String model;
        String year;
        String company;
        String plate;
      
        Car(String clr, String mdl, String yr, String com, String pla){
            this.color = clr;
            this.model = mdl;
            this.year = yr;
            this.company = com;
            this.plate = pla;
        }
      
        public void introduceSelf(){
            System.out.println("This is a"+ " " + this.color + " " + this.year + " " + this.company + " " + this.model + " with plate " + this.plate);
        }
      
           public static void main(String[] args){
         String arrModel[] = {"Corolla", "Mustang", "Cavalier", "LaSabre", "Civic",
                              "Accord", "Avalon", "Escalade", "XTS", "A220", "Crown Victoria"}; // Car models
         String arrPlate[] = {"11111", "22222", "33333", "44444", "55555",
                                "66666", "77777", "88888", "99999", "00000"}; // car plates
         String arrCompany[] = {"Toyota", "Ford", "Cheverolet", "Buick", "Honda",
                                "Honda", "Toyota", "Cadillac", "Cadillac", "Mercedes Benz", "Ford"}; // car company
         String arrColor[] = {"Red", "White", "White", "Green", "Black",
                               "Green", "Blue", "Black", "Orange", "Brown", "Blue"}; // car color
         String arrYear[] = {"2015", "2019", "1987", "2020", "2020",
                                "2001", "2004", "2016", "2010", "1991"}; // car year
                       
           Car arrCar[] = new Car[50];
           for (int i = 0; i < 10; i++){
               Car c = new Car(arrColor[i], arrYear[i], arrCompany[i], arrModel[i], arrPlate[i]);
               arrCar[i] = c;
           }
           
            for(int i = 0; i < 10; i++){
                arrCar[i].introduceSelf();
            }
           
         }
    }
              

I read the book, and my teachers notes are too vague. All she says to do is the following for the input part

    public static in getInt() throws IOException{
      String str = getString();
      return Integer.parseInt(str);
    }

    public static string getString() throws IOException{
         InputStreamReader isr = new InputStreamReader(System.in);
          BufferedReader br = new BufferedReader(isr);
           String str = br.readline();
             return s;
    }

Now what I'm thinking is I could do the following; 1- display, 2- insert, 3- search, 4-delete and use the scanner method

    Scanner scan = new Scanner(System.in)
      System.out.println("Choose what you would like to do: ");
        int option = scan.nextInt();
         arrOpt = new int[option];

Then I'm thinking of using a while statement, then if/else/if else for search, dipslay, insert, delete. Would that work or is there an easier method? I'm still doing research on how to do this, but in the mean time am posting here for some possible guidance as well.

Here is what I'm thinking of putting in the while statement

     for(int i=0; i < option; i++){
     array.del[i] = scan.nextInt(); //this would delete the car
            }

Right there I'm not sure how I can have the user choose which car to delete.

Answer 1

//solution is creating a user operative version.
//where user chooses the option to search , add,delete and print
//i have added few functionality and it also handles the invalid input.

//------------ Car.java--------------
import java.util.Scanner;
public class Car
{
   String color;
   String model;
   String year;
   String company;
   String plate;
  
   Car(String clr, String mdl, String yr, String com, String pla){
       this.color = clr;
       this.model = mdl;
       this.year = yr;
       this.company = com;
       this.plate = pla;
   }
  
   public void introduceSelf()
   {
       System.out.println("This is a"+ " " + this.color + " " + this.year + " " + this.company + " " + this.model + " with plate " + this.plate);
   }
   public static void printMenu()
   {
       System.out.println("\n--------- Menu ------------\n");
       System.out.println("1. Display");
       System.out.println("2. Insert");
       System.out.println("3. Search");
       System.out.println("4. Delete");
       System.out.println("0. Exit");
       System.out.print("Enter your choice: ");
   }
   public static int getChoice()
   {
       int choice=0;
       boolean isValid = false;
       //create Scanner object to take input from user.
       Scanner in = new Scanner(System.in);
       //while user enters valid choice.
       while(!isValid)
       {
           printMenu();
           try
           {
               choice = in.nextInt();
               //if entered number is integer
               //then check if it is in the bounds of valid choices given in menu.
               if(choice <0 || choice >4)
               {
                   System.out.println("\nError: Invalid choice entered");
               }
               else
               {
                   //if valid then set isValid to true. to break from loop
                   isValid = true;
               }
           }
           //if invalid text entered as input
           catch(Exception e)
           {
               //then catch that ioexception and print error message
               System.out.println("\nError: Invalid choice entered");
           }
       }
       return choice;
   }
   public static boolean insert(Car cars[],Car car,int carsInserted)
   {
       if(carsInserted<cars.length)
       {
           int ind = search(cars,car.plate,carsInserted);
           if(ind == -1)
           {
               cars[carsInserted] = car;
               return true;
           }
           else
           {
               System.out.println("\nError: Duplicate car, Car with plate number already existed\n");
               return false;
           }
       }
       else
       {
           System.out.println("\nError: Array is filled");
           return false;
       }
   }
   public static boolean delete(Car cars[],String plate,int carsInserted)
   {
       if(carsInserted == 0)
       {
           System.out.println("\nError: There are no cars to delete");
           return false;
       }
       else
       {
           int ind = search(cars,plate,carsInserted);
           if(ind == -1)
           {
               return false;
           }
           else
           {
               for(int j = ind;j<carsInserted-1;j++)
               {
                   cars[j] = cars[j+1];
               }
               return true;
           }
       }
   }
   public static int search(Car cars[],String plate,int carsInserted)
   {
       if(carsInserted == 0)
       {
           return -1;
       }
       else
       {
           for(int i = 0;i<carsInserted;i++)
           {
               if(cars[i].plate.equals(plate))
               {
                   return i;
               }
           }
           return -1;
       }
   }
   public static void display(Car cars[],int carsInserted)
   {
       if(carsInserted == 0)
       {
           System.out.println("\nError: There are no cars to Display");
       }
       else
       {
           System.out.println("\n---------- Total Cars : "+carsInserted+" ------------\n");
           for(int i = 0;i<carsInserted;i++)
           {
               cars[i].introduceSelf();
           }
       }
   }
   public static Car getCar()
   {
       Car car = null;
       String color;
       String model;
       String year;
       String company;
       String plate;
      
       Scanner in = new Scanner(System.in);
       System.out.print("\nEnter Car Color: ");
       color = in.nextLine().trim();
       if(color.equals(""))
       {
           System.out.println("Error: Car Color must not empty. ");
           return null;
       }
      
       System.out.print("\nEnter Car Model: ");
       model = in.nextLine().trim();
       if(model.equals(""))
       {
           System.out.println("Error: Car Model must not empty. ");
           return null;
       }
      
       System.out.print("\nEnter Car Year: ");
       year = in.nextLine().trim();
       if(year.equals(""))
       {
           System.out.println("Error: Car Year must not empty. ");
           return null;
       }
       try
       {
           int num = Integer.parseInt(year);
           if(num<1)
           {
               System.out.println("\nError: Invalid year entered");
               return null;
           }
       }
       catch(Exception e)
       {
           System.out.println("\nError: Invalid year entered");
           return null;
       }
      
       System.out.print("\nEnter Car Company: ");
       company = in.nextLine().trim();
       if(company.equals(""))
       {
           System.out.println("Error: Car Company must not empty. ");
           return null;
       }
      
       System.out.print("\nEnter Car Plate: ");
       plate = in.nextLine().trim();
       if(plate.equals(""))
       {
           System.out.println("Error: Car Plate must not empty. ");
           return null;
       }
       car = new Car(color,model,year,company,plate);
       return car;
   }
   public static void main(String[] args)
   {
       String arrModel[] = {"Corolla", "Mustang", "Cavalier", "LaSabre", "Civic",
                       "Accord", "Avalon", "Escalade", "XTS", "A220", "Crown Victoria"}; // Car models
       String arrPlate[] = {"11111", "22222", "33333", "44444", "55555",
                           "66666", "77777", "88888", "99999", "00000"}; // car plates
       String arrCompany[] = {"Toyota", "Ford", "Cheverolet", "Buick", "Honda",
                           "Honda", "Toyota", "Cadillac", "Cadillac", "Mercedes Benz", "Ford"}; // car company
       String arrColor[] = {"Red", "White", "White", "Green", "Black",
                       "Green", "Blue", "Black", "Orange", "Brown", "Blue"}; // car color
       String arrYear[] = {"2015", "2019", "1987", "2020", "2020",
                           "2001", "2004", "2016", "2010", "1991"}; // car year
                 
   Car arrCar[] = new Car[50];
   Scanner in = new Scanner(System.in);
   int carsInserted = 0;
   //add first 10 cars.
   for (int i = 0; i < 10; i++)
   {
       Car c = new Car(arrColor[i], arrYear[i], arrCompany[i], arrModel[i], arrPlate[i]);
       arrCar[i] = c;
       carsInserted++;
   }
     
   int choice;
   do
   {
       choice = getChoice();
       switch(choice)
       {
         
           case 1:
               {
                   display(arrCar,carsInserted);
                  
                   break;
               }
               case 2:
               {
                   Car car = getCar();
                   if(car == null)
                   {
                       System.out.println("\nSorry, Unable to insert car due to invalid input");
                   }
                   else
                   {
                       if(insert(arrCar,car,carsInserted))
                       {
                           System.out.println("\nSuccessfully inserted Car");
                           carsInserted++;
                       }
                       else
                       {
                           System.out.println("\nSorry, Unable to insert car due to invalid input");
                       }
                   }
                  
                  
                   break;
               }
               case 3:
               {
                   String plate;
                   System.out.print("\nEnter Car Plate: ");
                   plate = in.nextLine().trim();
                   if(plate.equals(""))
                   {
                       System.out.println("Error: Car Plate must not empty. ");
                   }
                   else
                   {
                       int ind = search(arrCar,plate,carsInserted);
                       if(ind != -1)
                       {
                           System.out.println("\nSuccessfully Found Car.Details: ");
                           arrCar[ind].introduceSelf();
                       }
                       else
                       {
                           System.out.println("\nUnbale to find Entered plate");
                       }
                   }
                   break;
               }
               case 4:
               {
                   String plate;
                   System.out.print("\nEnter Car Plate: ");
                   plate = in.nextLine().trim();
                   if(plate.equals(""))
                   {
                       System.out.println("Error: Car Plate must not empty. ");
                   }
                   else
                   {
                       if(delete(arrCar,plate,carsInserted))
                       {
                           System.out.println("\nSuccessfully Deleted Car\n");
                           carsInserted--;
                       }
                       else
                       {
                           System.out.println("\nUnbale to find Entered plate");
                       }
                   }
                   break;
               }
               case 0:
                   System.out.println("\nQutting...");
                   break;
       }
       }while(choice != 0);
   }
}

//PLEASE LIKE THE ANSWER AND COMMENT IF YOU HAVE DOUBTS.

/*

------------- OUTPUT -1 -----------

--------- Menu ------------

1. Display
2. Insert
3. Search
4. Delete
0. Exit
Enter your choice: 1

---------- Total Cars : 10 ------------

This is a Red Toyota Corolla 2015 with plate 11111
This is a White Ford Mustang 2019 with plate 22222
This is a White Cheverolet Cavalier 1987 with plate 33333
This is a Green Buick LaSabre 2020 with plate 44444
This is a Black Honda Civic 2020 with plate 55555
This is a Green Honda Accord 2001 with plate 66666
This is a Blue Toyota Avalon 2004 with plate 77777
This is a Black Cadillac Escalade 2016 with plate 88888
This is a Orange Cadillac XTS 2010 with plate 99999
This is a Brown Mercedes Benz A220 1991 with plate 00000

--------- Menu ------------

1. Display
2. Insert
3. Search
4. Delete
0. Exit
Enter your choice: 2

Enter Car Color: red

Enter Car Model: toyota

Enter Car Year: k

Error: Invalid year entered

Sorry, Unable to insert car due to invalid input

--------- Menu ------------

1. Display
2. Insert
3. Search
4. Delete
0. Exit
Enter your choice: 1

---------- Total Cars : 10 ------------

This is a Red Toyota Corolla 2015 with plate 11111
This is a White Ford Mustang 2019 with plate 22222
This is a White Cheverolet Cavalier 1987 with plate 33333
This is a Green Buick LaSabre 2020 with plate 44444
This is a Black Honda Civic 2020 with plate 55555
This is a Green Honda Accord 2001 with plate 66666
This is a Blue Toyota Avalon 2004 with plate 77777
This is a Black Cadillac Escalade 2016 with plate 88888
This is a Orange Cadillac XTS 2010 with plate 99999
This is a Brown Mercedes Benz A220 1991 with plate 00000

--------- Menu ------------

1. Display
2. Insert
3. Search
4. Delete
0. Exit
Enter your choice: 2

Enter Car Color: red

Enter Car Model: toyota

Enter Car Year: 2010

Enter Car Company: corolla

Enter Car Plate: 11111

Error: Duplicate car, Car with plate number already existed

Sorry, Unable to insert car due to invalid input

--------- Menu ------------

1. Display
2. Insert
3. Search
4. Delete
0. Exit
Enter your choice: 2

Enter Car Color: red

Enter Car Model: toyota

Enter Car Year: 2019

Enter Car Company: corolla

Enter Car Plate: 12345

Successfully inserted Car

--------- Menu ------------

1. Display
2. Insert
3. Search
4. Delete
0. Exit
Enter your choice: 1

---------- Total Cars : 11 ------------

This is a Red Toyota Corolla 2015 with plate 11111
This is a White Ford Mustang 2019 with plate 22222
This is a White Cheverolet Cavalier 1987 with plate 33333
This is a Green Buick LaSabre 2020 with plate 44444
This is a Black Honda Civic 2020 with plate 55555
This is a Green Honda Accord 2001 with plate 66666
This is a Blue Toyota Avalon 2004 with plate 77777
This is a Black Cadillac Escalade 2016 with plate 88888
This is a Orange Cadillac XTS 2010 with plate 99999
This is a Brown Mercedes Benz A220 1991 with plate 00000
This is a red 2019 corolla toyota with plate 12345

--------- Menu ------------

1. Display
2. Insert
3. Search
4. Delete
0. Exit
Enter your choice: 3

Enter Car Plate: 12345

Successfully Found Car.Details:
This is a red 2019 corolla toyota with plate 12345

--------- Menu ------------

1. Display
2. Insert
3. Search
4. Delete
0. Exit
Enter your choice: 3

Enter Car Plate: 2s

Unbale to find Entered plate

--------- Menu ------------

1. Display
2. Insert
3. Search
4. Delete
0. Exit
Enter your choice: 3

Enter Car Plate: 88888

Successfully Found Car.Details:
This is a Black Cadillac Escalade 2016 with plate 88888

--------- Menu ------------

1. Display
2. Insert
3. Search
4. Delete
0. Exit
Enter your choice: 4

Enter Car Plate: 111112

Unbale to find Entered plate

--------- Menu ------------

1. Display
2. Insert
3. Search
4. Delete
0. Exit
Enter your choice: 4

Enter Car Plate: 11111

Successfully Deleted Car

--------- Menu ------------

1. Display
2. Insert
3. Search
4. Delete
0. Exit
Enter your choice: 1

---------- Total Cars : 10 ------------

This is a White Ford Mustang 2019 with plate 22222
This is a White Cheverolet Cavalier 1987 with plate 33333
This is a Green Buick LaSabre 2020 with plate 44444
This is a Black Honda Civic 2020 with plate 55555
This is a Green Honda Accord 2001 with plate 66666
This is a Blue Toyota Avalon 2004 with plate 77777
This is a Black Cadillac Escalade 2016 with plate 88888
This is a Orange Cadillac XTS 2010 with plate 99999
This is a Brown Mercedes Benz A220 1991 with plate 00000
This is a red 2019 corolla toyota with plate 12345

--------- Menu ------------

1. Display
2. Insert
3. Search
4. Delete
0. Exit
Enter your choice: 0

Quitting...

*/