Reverse Strings using rercursion and iteration

Question

Hi,
I really need some help, am quite new to java and am struggling.
I want to design 2 methods, both 2 reverse strings.
1) uses StringBuffer and iteration
2) uses Strings and recursion
I would be greatful for any advice or help.
Thanx xxxxx Nats xxxxxx

Answer 1

Oh, you need to do it using both methods.... Sorry, didn't realise it was coursework :)
Using StringBuffer and iteration
public StringBuffer reverse(StringBuffer buff) {
    int halfLen = buff.length();
    int len = buff.length();
    for(int i=0; i < halfLen; i++) {
         char c1 = buff.getCharAt(i);
         char c2 = buff.getCharAt((len - i) - 1);
         buff = buff.setCharAt(i, c2);
         buff = buff.setCharAt((len - i) - 1, c1);
    return buff;
}And for String using recursion
public String reverse(String str) {
    char[] chars = new char[str.length];
    str.getChars(0, chars, 0, str.length());
    reverseChars(chars, 0, str.length() / 2);
    return new String(chars);  
private reverseChars(char[] chars, int index, int halfLen) {
    //* end condition
    if(index >= halfLen) return;
    topIndex = (chars.length - 1) - index;
    char tmp = chars[index];
    chars[index] = chars[topIndex];
    chars[topIndex] = tmp;
    reverseChars(chars, ++index, halfLen);
}I only wrote this code on the fly so things may break but it is a start.