Java Programming Problems.Converting a character into uppercase or lowercase?

Question

/**

* @(#)lowercasesandupper.java

*

*

* @author

* @version 1.00 2008/8/5

*/

import javax.swing.JOptionPane;

import java.io.*;

import java.util.*;

import java.lang.*;

public class lowercasesandupper {

public static void main(String[]args)

{

String message;

int i;

String letter;

char let;

message=JOptionPane.showInputDialog("E... the string: ");

message.length();

for(i=0;i<message.length();i++)

{

let = message.charAt(i);

if(let == let.toUpperCase())

{

System.out.print(""+let.toLowerCase())...

}

else

{

System.out.print(""+let.toUpperCase()...

}

}

}

}

//ERROR OF THE PROGRAM:

char cannot be dereferenced

char cannot be dereferenced

char cannot be dereferenced

Answer 1

Problem:

Cannot invoke toUpperCase() on the primitive type char

i) let.toUpperCase()

ii)let.toLowerCase()

iii)let.toUpperCase()

Solution:

User Wrapper Class Character

import javax.swing.JOptionPane;

import java.io.*;

import java.util.*;

import java.lang.*;

public class lowercasesandupper {



public static void main(String[]args)

{

String message;

int i;

String letter;

Character let;

message=JOptionPane.showInputDialog(&quot;E... the string: &quot;);

//message.length();

for(i=0;i&lt;message.length();i++)

{

let = message.charAt(i);

if(let == Character.toUpperCase(i))

{

System.out.print(&quot;&quot;+Character.toLowerC...

}

else

{

System.out.print(&quot;&quot;+Character.toUpperC...

}

}

}

}

hope this will help

Cheers:)