Swap characters in a string.

For one assignment I just got today, I need to take a string and swap every other character. If the string is an odd length, leave the last character alone.

i cant ONLY use .length(), .charAt(), and .substring methods from the string class. NOTHING ELSE!

Examples:
IN: laptop OUT: altppo
IN: speaker OUT: psaeekr

Any suggestions on how to go about this?

Thanks a million in advance!

In String you are having a method toCharArray[].using this u make character array and use the swapping algorithm.


public class SwapLetters
{

public SwapLetters()
{
}

public static void main(String args[])
{
if(args.length == 0)
{
System.out.println("Supply a string(without whitespace) as argument");
System.exit(0);
}
SwapLetters swapletters = new SwapLetters();
if(args[0].length() % 2 == 0)
{
System.out.println((new StringBuilder()).append("Swapped string --> ").append(swapletters.getSwappedString(args[0])).toString());
} else
{
int i = args[0].length();
String s = args[0].substring(0, i - 1);
System.out.println((new StringBuilder()).append("Swapped string --> ").append(swapletters.getSwappedString(s)).append( args[0].substring(i - 1)).toString());
}
}

public String getSwappedString(String s)
{
s = s.trim();
int i = s.length();
char ac[] = s.toCharArray();
char ac1[] = new char[ac.length];
for(int j = 0; j < i; j++)
if(j % 2 == 0)
{
ac1[j + 1] = ac[j];
ac1[j] = ac[j + 1];
}

s = new String(ac1);
return s;
}
}

I appreciate your help, however I cannot use an array. ONLY .length(), .charAt(), and .substring().

Quote:

---

Originally Posted by Sdannenberg3

For one assignment I just got today, I need to take a string and swap every other character. If the string is an odd length, leave the last character alone.

i cant ONLY use .length(), .charAt(), and .substring methods from the string class. NOTHING ELSE!

---

How inefficient, but nevertheless here goes:

Pairwise swaps work as follows:

1) if the length of a String s is less than two, just return the String s;

otherwise

2) swap the first two characters of s and concatenate the result of the pairwise swap of the rest of the String to it.

Recursion comes in naturally here ...

kind regards,

Jos

Try this:

Code:

---

package Testing;
import java.util.*;
public class BoredLol {
    public static void main(String[] args){
        Scanner sin = new Scanner(System.in);
        String sWord = sin.next();
        while(sWord.length()>1){
            System.out.print(sWord.charAt(1));
            System.out.print(sWord.charAt(0));
            sWord = sWord.substring(2);
        }
        System.out.println(sWord);
    }
}

---