true/false

[Energizer100]

Hey guys.

I'm having trouble returning true and false things in java.

import java.io.*;
 
public class StringUtil 
{
    public static void main(String args[]) throws IOException
    {
        BufferedReader reverseString = new BufferedReader(new InputStreamReader(System.in));
        String revString;
        BufferedReader palindromeString = new BufferedReader(new InputStreamReader(System.in));
        String palString;
        BufferedReader pigLatinString = new BufferedReader(new InputStreamReader(System.in));
        String plString;
        BufferedReader shortHandString = new BufferedReader(new InputStreamReader(System.in));
        String shString;
        int i = 0;
        int indexPalString = 0;
 
        System.out.println("Enter a potential Palindrome:");
            palString = palindromeString.readLine();
            indexPalString = palString.length() - 1;
 
        for(i = 0; i <= indexPalString; i++)
        {
            if (palString.charAt(i) == palString.charAt(indexPalString - i))
            {
                return true;
            }
            else{
                return false;
            }
        }
    }
}
 

I want it to check whether or not it is a palindrome. It HAS to return true or false.
And is there anyway that i could ignore case, spaces, and punctuation?

Thank You

[JosAH]

Two small questions to you:

1) What are all those BufferedReaders doing there?
2) your main method is supposed to return nothing (a void); why HAS it supposed
to return a boolean value?

kind regards,

Jos

[Energizer100]

Two small questions to you:

1) What are all those BufferedReaders doing there?
2) your main method is supposed to return nothing (a void); why HAS it supposed
to return a boolean value?

kind regards,

Jos

The buffered readers are there because that's what i used in one of my other program for inputted characters.

So should i put all of the calculations before the main method?

[Laharl]

From the sounds of it, you either need to write a function to check for palindromes that would return a boolean, and call it in your main, or print whether or not it is a palindrome in your main rather than trying to return something to a void function.

[Energizer100]

From the sounds of it, you either need to write a function to check for palindromes that would return a boolean, and call it in your main, or print whether or not it is a palindrome in your main rather than trying to return something to a void function.

import java.util.Scanner;
import java.io.*;

public class StringUtil
{
public static void main(String args[])
{
Scanner reverseString = new Scanner(System.in);
String revString;
Scanner palindromeString = new Scanner(System.in));
String palString;
Scanner pigLatinString = new Scanner(System.in));
String plString;
Scanner shortHandString = new Scanner(System.in));
String shString;
int i = 0;
int indexPalString = 0;

System.out.println("Enter a potential Palindrome:");
palString = palindromeString.readLine();
indexPalString = palString.length() - 1;

for(i = 0; i <= indexPalString; i++)
{
if (palString.charAt(i).equals(palString.charAt(index PalString - i)))
{
System.out.println("True");
}
else{
System.out.println("False");
}
}


}
}


When i run it, it says true/false for every letter. how do i stop that?

[Laharl]

Move one of those printing statements outside the loop, but leave the other where it is, and use a boolean to cover whether or not it is a palindrome. You can use the break; keyword to leave the loop at any time, assuming it works the same as in C++.

Eg:

 \\Code that checks if two strings are equal, and prints out if they are-assumes they have the same length
String s = "Hi";
String t = "Bi";
for (int a = 0; a < s.length(); a++){
    if (s.charAt(a) != t.charAt(a)){
       System.out.println(s+" and " +t+" are not the same.");
       break;
   }
}
if (a == s.length())
      System.out.println("These are the same.");
 

Can you extrapolate the code you need from here?

[Energizer100]

Move one of those printing statements outside the loop, but leave the other where it is, and use a boolean to cover whether or not it is a palindrome. You can use the break; keyword to leave the loop at any time, assuming it works the same as in C++.

Eg:

 \\Code that checks if two strings are equal, and prints out if they are-assumes they have the same length
String s = "Hi";
String t = "Bi";
for (int a = 0; a < s.length(); a++){
    if (s.charAt(a) != t.charAt(a)){
       System.out.println(s+" and " +t+" are not the same.");
       break;
   }
}
if (a == s.length())
      System.out.println("These are the same.");
 

Can you extrapolate the code you need from here?

hmmm. ill try adding the break statement, and see if it works

It does.

import java.util.Scanner;
import java.io.*;

public class StringUtil
{
public static void main(String args[]) throws IOException
{
BufferedReader reverseString = new BufferedReader(new InputStreamReader(System.in));
String revString;
BufferedReader palindromeString = new BufferedReader(new InputStreamReader(System.in));
String palString;
BufferedReader pigLatinString = new BufferedReader(new InputStreamReader(System.in));
String plString;
BufferedReader shortHandString = new BufferedReader(new InputStreamReader(System.in));
String shString;
int i = 0;
int indexPalString = 0;

System.out.println("Enter a potential Palindrome:");
palString = palindromeString.readLine();
indexPalString = palString.length() - 1;

for(i = 0; i <= indexPalString; i++)
{
if (palString.charAt(i) != palString.charAt(indexPalString - i))
{
System.out.println("False");
break;
}
else{
System.out.println("True");
break;
}
}


}
}


Where do i put the ignore case stuff? And is there a way to ignore punctuation and spaces? So if someone were to write Race Car, it would return true.

[Laharl]

You're very close, but your current code will only check the first character against the last and then break the loop because either they are equal, in which case you print that out and break, or they aren't, in which case you print that and break. You only want to break the loop in one of those two cases and can't deal with the other case until after the loop, so you'll need to move your print statements around. Can you see how to do that?

[Energizer100]

You're very close, but your current code will only check the first character against the last and then break the loop because either they are equal, in which case you print that out and break, or they aren't, in which case you print that and break. You only want to break the loop in one of those two cases and can't deal with the other case until after the loop, so you'll need to move your print statements around. Can you see how to do that?

I don't know how to do that. I tried moving the break around and nothing happened. But i don't know why i have to move the output statements around

[Laharl]

You have to move the True print statement outside the loop because you can't conclude true unles it clears the loop without breaking prematurely. Can you see how to check whether or not you've got that case (and thus need to output True)? As a hint, the example code I gave you earlier is close to what you need.

[Energizer100]

You have to move the True print statement outside the loop because you can't conclude true unles it clears the loop without breaking prematurely. Can you see how to check whether or not you've got that case (and thus need to output True)? As a hint, the example code I gave you earlier is close to what you need.

import java.util.Scanner;
import java.io.*;

public class StringUtil
{
public static void main(String args[]) throws IOException
{
BufferedReader reverseString = new BufferedReader(new InputStreamReader(System.in));
String revString;
BufferedReader palindromeString = new BufferedReader(new InputStreamReader(System.in));
String palString;
BufferedReader pigLatinString = new BufferedReader(new InputStreamReader(System.in));
String plString;
BufferedReader shortHandString = new BufferedReader(new InputStreamReader(System.in));
String shString;
int i = 0;
int indexPalString = 0;

System.out.println("Enter a potential Palindrome:");
palString = palindromeString.readLine();
indexPalString = palString.length() - 1;

for(i = 0; i <= indexPalString; i++)
{
if (palString.charAt(i) != palString.charAt(indexPalString - i))
{
System.out.println("False");
break;
}
}
if (palString.charAt(i) == palString.charAt(indexPalString - 1))
System.out.println("True");
}
}


When i run it, there is an error message for something like "bob". I reviewed the code again and I don't know what's wrong

[Energizer100]

import java.util.Scanner;
import java.io.*;

public class StringUtil
{
public static void main(String args[]) throws IOException
{
BufferedReader reverseString = new BufferedReader(new InputStreamReader(System.in));
String revString;
BufferedReader palindromeString = new BufferedReader(new InputStreamReader(System.in));
String palString;
BufferedReader pigLatinString = new BufferedReader(new InputStreamReader(System.in));
String plString;
BufferedReader shortHandString = new BufferedReader(new InputStreamReader(System.in));
String shString;
int i = 0;
int indexPalString = 0;

System.out.println("Enter a potential Palindrome:");
palString = palindromeString.readLine();
indexPalString = palString.length() - 1;

for(i = 0; i <= indexPalString; i++)
{
if (palString.charAt(i) != palString.charAt(indexPalString - i))
{
System.out.println("False");
break;
}
}
if (palString.charAt(i) == palString.charAt(indexPalString - 1))
System.out.println("True");
}
}


When i run it, there is an error message for something like "bob". I reviewed the code again and I don't know what's wrong

Never mind, i got it