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I'm creating an application that converts a 5 digit zip code into frame bars. Weirdly, the first digit entered doesn't correctly go through the conversion. Here's the code:

import java.util.*;
import java.lang.*;
import java.io.*;
class Zip

 public static String checkDigit(String bar)
 
 Scanner s = new Scanner(System.in);
 int input;
 input = new int [4];
 for(int p = 0; p < 4; p++)
 
 input[p] = s.nextInt();
 if (input[p] == 0)
 :::";
 
 if (input[p] == 1)
 
 
 System.out.println();
 return bar;
 

 public static void main (String args) 
 Scanner s = new Scanner(System.in);
 System.out.println(checkDigit(s.nextLine())); 
 

For example, when entering 1, 0, 0, 0, 0 into the array, the output is

"1||:::||:::||:::||:::"

When entering 0, 1, 1, 1, 1 into the array, the output is

"0:::||:::||:::||:::||"

Instead of converting the first digit at pos [0], it just prints the number outright. Why is this?

It is because of s.nextLine() it will read the first int entered in console and save it in String bar passing into checkDigit()

Scanner s = new Scanner(System.in);
 System.out.println(checkDigit(s.nextLine())); 

Pass an empty string

Scanner s = new Scanner(System.in);
 System.out.println(checkDigit("")); 

Input : 0 1 1 1

Output : ||::::::||:::||:::||

There's not much of a problem here actually @ddalcanto. Your logic is pretty much alright.. Just a few minor mistakes which are causing the anomalies in the output.

1. The 1st input is displayed as it is because you are appending the updated values to the bar string which is nothing but the first accepted character because of the s.nextLine() in the main() function. Hence, see point number 2.


2. There's no need to send the s.nextLine() as argument to the function call of checkDigit(). Also remove the string bar as parameter from the function definition too. This is what is causing you to give an extra input. For example, 5 inputs for intended 4 inputs, etc.


3. Your input array is of size 4, but you are looping from 0 to 4, which means 5 times to get 5 inputs, but the array can hold just 4 elemnts. Just change the array size to 5. => input = new int[5];
   

Here is the updated working code along with the associated output.

CODE:

import java.util.*;
import java.lang.*;
import java.io.*;
class Zip

 public static String checkDigit()
 
 Scanner s = new Scanner(System.in);
 String bar = "";
 int input;
 input = new int [5];
 for(int p = 0; p < 5; p++)
 
 input[p] = s.nextInt();
 if (input[p] == 0)
 :::";
 
 if (input[p] == 1)
 
 
 System.out.println();
 return bar;
 

 public static void main (String args) 
 Scanner s = new Scanner(System.in);
 System.out.println(checkDigit()); 
 

OUTPUT:

 1
 1
 1
 1
 1

:::||:::||:::||:::||:::||

Another input-output pair:

 0
 1
 1
 0
 1

||::::::||:::||||::::::||

You are creating and reading from a Scanner object in main() so the first digit goes into the bar parameter sent to the checkDigit method.

I would remove the bar parameter altogether and also make some other changes.

public static String checkDigit() 
 StringBuilder bar = new StringBuilder();
 Scanner s = new Scanner(System.in);
 int input = 0;
 for(int p = 0; p < 5; p++) 
 input = s.nextInt();
 if (input == 0) 
 if (input == 1) ");
 
 
 return bar.toString();