Java Software Programming Examples For Beginners / Interview: How To Swap Integer (and String) Variables Without Using a Temporary Variable

Use Of try, Catch ,throw, throws & final plz give me the best website for this in Simple Language for Understanding this..

if(x > y)
{
x = x- y;
y = y + x;
x = y - x;
}
else
{
y = y - x;
x = x + y;
y = x - y;
}

import java.io.*;
class ab
{
public static void main(String arg[]) throws IOException
{
int x=6;
if(x=6)
{
System.out.println(”Hi…”);
}
}
}

the question is .. Is it possible to run this program with out changing if(x=6)

im coding a anagram word game to swap letters from one label to another (up to the down) by using a threeBottons class how should i use the string and char code? (the second character of label one should place to the second character of label two) i need that much help thanks

Unfortunately, the code to exchange integer values will fail for values that cause over- or underflow.

x = x + y;
y = x - y;
x = x - y;

However, you can use exclusive-or (xor), which is like add without carry. The following unobvious code exchanges all int values.

x = x ^ y;
y = x ^ y;
x = x ^ y;

@Robert
I like that. It looks cleaner.

x = x + y;
y = x.substring(0, x.length() - y.length());
x = x.substring(y.length());

The string sample will fail if the string x contains the string y. For example,

String x = “Hello World”;
String y = “Hello”;

Step 1: x = x + y;

x = “Hello WorldHello”

Step 2: y = x.substring(0, x.indexOf(y));

x.indexOf(y) = 0, so y = “”;

Step 3: x = x.substring(x.indexOf(y) + y.length());

x.indexOf(y) = 0 and y.length = 0, so x = “Hello WorldHello”

You can fix this by using lastIndexOf() method in String like

x = x + y;
y = x.substring(0, x.lastIndexOf(y));
x = x.substring(x.indexOf(y) + y.length());

or you could eliminate the indexOf() calculations altogether and just use the lengths of the strings

x = x + y;
y = x.substring(0, x.length() - y.length());
x = x.substring(y.length());

BTW: I actually asked this question today while interviewing candidates.

@Jack & Alexey
Oops!
Thanks for the catch. Corrected.

Just checking if you are attentive

Maybe

x = x + y;
y = x - y;
x = x - y;

x = x+y;
y = x-y;
x = x-y;

x : 1 y : 2

x = x + y;
x : 3 y : 2

x = x - y;
x : 1 y : 2

y = x - y;
x : 1 y : -1