如果String.charAt（i）遇到空格，则会中断程序

Question

Following code basically replaces characters in a string with reverse characters in ABC..

Eg. if user inputs- AbC

Then result would be ZyX

My Problem is, if the input contains a space then it breaks the code and does not continue the execution.

import java.util.*;

public class HelloWorld{

     int[] capitals = new int[26];
     int[] smalls = new int[26];
     public static void main(String []args){
         HelloWorld rs=new HelloWorld();
         rs.Initialize();

         rs.Encode();
     }

     public void Encode()
     {
         Scanner reader = new Scanner(System.in);
         System.out.println("Enter string: ");
         String input = reader.next();

         //System.out.println("User entered: " + input);
         String newString="";
         int pos=0;
         for (int in = 0; in < input.length(); in++)
         {
             if(input.charAt(in) == ' ')
             {
                newString += " ";
             }
             else
             {
                if((int)input.charAt(in) >= 65 && (int)input.charAt(in) <= 90)
                {
                    for(int i = 0; i< 26; i++) {
                        if((int)input.charAt(in) == capitals[i]) {
                            newString += (char)capitals[25-i];
                        }
                    }
                }
                else if((int)input.charAt(in)>=97 && (int)input.charAt(in) <= 122)
                {
                    for(int i = 0; i< 26; i++) {
                        if((int)input.charAt(in) == smalls[i]) {
                            newString += (char)smalls[25-i];
                        }
                    }
                }
                else
                {
                    if(input.charAt(in) == ' ')
                        newString += " ";
                    else
                        newString += input.charAt(in);
                }

             }
            pos = 0;
         }
         System.out.println(newString);
     }


     public void Initialize()
     {
        int pos=0;
        for (int i=65;i<=90;i++)
        {
             capitals[pos] = i;
             smalls[pos]= i + 32;
             pos++;
        }
     }
}

What wrong am I doing?

Answer 1

Calling Scanner.next()

Finds and returns the next complete token from this scanner.

Normally, a Scanner 's token is delineated by the space character. From that same page:

The default whitespace delimiter used by a scanner is as recognized by Character.isWhitespace.

So when you call Scanner.next() , it's only reading up until the first space and, since you never read from it again, the rest of the input is discarded when the program ends.

If you want everything the user enters, use nextLine instead.

Answer 2

According to the Javadoc

next() Finds and returns the next complete token from this scanner.

The space is a delimter, so the next token is always the first part of the string before the space character.

You can set up the delimter pattern as explained here:

http://docs.oracle.com/javase/7/docs/api/index.html