CodeGym/Help with Java Tasks/What is wrong in my code?

Level 23

Solec-Zdroj

21.02.2019
1819views
18comments

What is wrong in my code?

Question about the task

Different methods for different types

Java Core, Level 5, Lesson 12

Under discussion

need help

1. Read data from the console until the word "exit" is entered.
2. For each value (except "exit"), call the print method. If the value:
2.1. contains a period ("."), then call the print method for Double;
2.2. is greater than zero, but less than 128, then call the print method for short;
2.3. less than or equal to zero or greater than or equal to 128, then call the print method for Integer;
2.4. otherwise, call the print method for String.

Requirements:

The program must read data from the keyboard.
The program should stop reading data from the keyboard after "exit" is entered.
If the entered string contains a period (".") and can be correctly converted to a Double, the print(Double value) method should be called.
If the entered string can be correctly converted to a short and the resulting number is greater than 0, but less than 128, the print(short value) method should be called.
If the entered string can be correctly converted to an Integer and the resulting number is less than or equal to 0 or greater than or equal to 128, the print(Integer value) method should be called.
In all other cases, the print(String value) method should be called.

package com.codegym.task.task15.task1519; import java.io.BufferedReader; import java.io.InputStreamReader; import java.io.IOException; /* Different methods for different types */ public class Solution { public static void main(String[] args) throws IOException { BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); while(true){ String a = reader.readLine(); byte y = Byte.parseByte(a); Integer p = Integer.parseInt(a); if(a.equals("exit")){ break; } else if(a.contains(".")){ Double x = Double.parseDouble(a); print(x); } else if(y>0 && y<128){ print(y); } else if(p<=0 && p>=128){ print(p); } else print(a); } //write your code here } public static void print(Double value) { System.out.println("This is a Double. Value: " + value); } public static void print(String value) { System.out.println("This is a String. Value: " + value); } public static void print(short value) { System.out.println("This is a short. Value: " + value); } public static void print(Integer value) { System.out.println("This is an Integer. Value: " + value); } }

Comments (18)

Popular
New
Old

You must be signed in to leave a comment

Guadalupe Gagnon

Level 37 , Tampa, United States

21 February 2019, 15:14

#1 line 19-21, the if statement that checks for 'exit', should be directly after the readline(). If any string is entered and you try parsing that to a byte or int, then the code will error out. #2 You should create a method that tries to parse the user input into an Integer, surrounded by a try-catch block, that returns true if the input parses succesfully, or false if an error is thrown (caught in the catch block). This will determine if the input is a number or a string. You can use it in an if block like

if (tryParse(a)){
  // actually convert it to a number
  // code to check if it should call the short method or integer method
}

Wojtek

Level 23 , Solec-Zdroj

21 February 2019, 15:41

Wojtek

Level 23 , Solec-Zdroj

21 February 2019, 15:42

i did this and only first two requirements are correct

Wojtek

Level 23 , Solec-Zdroj

21 February 2019, 15:47

I add this condition to print String else if (!a.contains(".")){ print(a); }

Wojtek

Level 23 , Solec-Zdroj

21 February 2019, 15:51

for : ArrayList<String> list = new ArrayList<>(); list.add("111"); list.add("rrt"); list.add("2"); list.add("33.6"); list.add("5"); list.add("ert"); list.add("1.445"); list.add("444"); output is: This is an Integer. Value: 111 This is a String. Value: rrt This is an Integer. Value: 2 This is a Double. Value: 33.6 This is an Integer. Value: 5 This is a String. Value: ert This is a Double. Value: 1.445 This is an Integer. Value: 444

Guadalupe Gagnon

Level 37 , Tampa, United States

21 February 2019, 15:52

change the lines inside the if (tryParse(a)) block to

int i = Integer.parseInt(a);
if(i <= 0 || i >= 128)
   print(i);
else
   print((short)i);

Wojtek

Level 23 , Solec-Zdroj

21 February 2019, 15:58

public class Solution {

    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        while(true){
            String a = reader.readLine();
            if(a.equals("exit")){
                break;
            }
            else if(a.contains(".")){
                Double d = Double.parseDouble(a);
                print(d);
            }
            if(tryParse(a)){
                int i = Integer.parseInt(a);
                if(i <= 0 || i >= 128)
                    print(i);
                else
                    print((short)i);
            }
            else if(!a.contains(".")){
                print(a);}
            }
        //write your code here
    }
     public static boolean tryParse(String w){
       try{
           Integer.parseInt(w);
           return true;
       }
       catch (Exception e){
           return false;
       }
     }
    public static void print(Double value) {
        System.out.println("This is a Double. Value: " + value);
    }

    public static void print(String value) {
        System.out.println("This is a String. Value: " + value);
    }

    public static void print(short value) {
        System.out.println("This is a short. Value: " + value);
    }

    public static void print(Integer value) {
        System.out.println("This is an Integer. Value: " + value);
    }
}

Wojtek

Level 23 , Solec-Zdroj

21 February 2019, 15:59

output seems to be ok but still only first two requirements are correct

Guadalupe Gagnon

Level 37 , Tampa, United States

21 February 2019, 16:14

change line 21 to just else

Wojtek

Level 23 , Solec-Zdroj

21 February 2019, 16:19

still the same

Wojtek

Level 23 , Solec-Zdroj

21 February 2019, 16:20

public class Solution {

    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        while(true){
            String a = reader.readLine();
            if(a.equals("exit")){
                break;
            }
            if(tryParse(a)){

                double i = Double.parseDouble(a);

                if(i/(int)i!=1){
                    print(i);
                }
                else if(i <= 0 || i >= 128)
                    print((int)i);
                else
                    print((short)i);

            }
            else
                print(a);
            }
        //write your code here
    }
     public static boolean tryParse(String w){
       try{
           Integer.parseInt(w);
           return true;
       }
       catch (Exception e){
           return false;
       }
     }
    public static void print(Double value) {
        System.out.println("This is a Double. Value: " + value);
    }

    public static void print(String value) {
        System.out.println("This is a String. Value: " + value);
    }

    public static void print(short value) {
        System.out.println("This is a short. Value: " + value);
    }

    public static void print(Integer value) {
        System.out.println("This is an Integer. Value: " + value);
    }
}

Wojtek

Level 23 , Solec-Zdroj

21 February 2019, 16:21

i changed while loop a little bit. Now 1st, 2nd and 4th requirements are correct

Guadalupe Gagnon

Level 37 , Tampa, United States

21 February 2019, 16:36

public class Solution {

    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        while(true){
            String a = reader.readLine();
            if(a.equals("exit")){
                break;
            }

            if(a.contains(".")){
                Double d = Double.parseDouble(a);
                print(d);
            }
            else if(tryParse(a)){
                int i = Integer.parseInt(a);
                if(i <= 0 || i >= 128)
                    print(i);
                else
                    print((short)i);
            }
            else {
                print(a);}
        }

    }
    public static boolean tryParse(String w){
        try{
            Integer.parseInt(w);
            return true;
        }
        catch (Exception e){
            return false;
        }
    }
    public static void print(Double value) {
        System.out.println("This is a Double. Value: " + value);
    }

    public static void print(String value) {
        System.out.println("This is a String. Value: " + value);
    }

    public static void print(short value) {
        System.out.println("This is a short. Value: " + value);
    }

    public static void print(Integer value) {
        System.out.println("This is an Integer. Value: " + value);
    }
}

Wojtek

Level 23 , Solec-Zdroj

21 February 2019, 17:29

and this code doesn't pass verification :)

Guadalupe Gagnon

Level 37 , Tampa, United States

21 February 2019, 17:46

I don't know why that code won't pass. I messaged you my solve. The only other idea is to change lines 17 and 18 to this:

if(i <= 0 || i >= 128) {
   Integer x = i;
   print(x);
}

Brandon Horvatic

Level 27 , Johannesburg, South Africa

16 September 2019, 19:30

Brandon Horvatic

Level 27 , Johannesburg, South Africa

16 September 2019, 19:31

My code was similar to yours and I had the same issue where I only passed the first two verifications. I changed it to this and it seemed to work.. Still does the same thing but for some reason one passes and the other doesn't..

Adam S

Level 22 , Gliwice, Poland

14 April 2020, 08:37

Hi, it's been a while since you've texted this issue, but I've been doing this task today and figured it out. The point is that your code throws a NumberFormatException when you enter e.g. some.text. So the exception has to be supported :

if (a.contains(".")) {
                try {
                    Double d = Double.parseDouble(a);
                    print(d);
                } catch (NumberFormatException e) {
                    print(a);
                }