字符串反写（学习）

今天想起了之前的一个问题，反写字符串的方法。

1、

public class shouxie {
    public static void main(String[] args) {
        String str = "abcdefghijklmnopqrstuvwxyz";
        int length = str.length();
        char[] chars =  str.toCharArray();
        for(int i = 0 ; i < length / 2 ; i ++){
            char temp;
            temp = chars[i];
            chars[i] = chars[length - 1 -i];
            chars[length -1 - i] = temp;
        }
        System.out.println(chars);
    }
}

2、

public class gest {
    public static void main(String[] args) {
        Scanner str = new Scanner(System.in);
//        String str2 = str.next();
        char[] str3 = str.next().toCharArray();
        List str4 = new ArrayList();
        for(int i = 0; i < str3.length; i ++){
            str4.add(str3[i]);
        }
        for (int j = str4.size() - 1; j >= 0; j --){
            System.out.print(str4.get(j));
        }
    }
}

3、

public class gest {
    public static void main(String[] args) {
        Scanner str = new Scanner(System.in);
//        String str2 = str.next();
        char[] str3 = str.next().toCharArray();
        List str4 = new ArrayList();
        StringBuffer str5 = new StringBuffer();
        for(int i = 0; i < str3.length; i ++){
            str4.add(str3[i]);
        }
        for (int j = str4.size() - 1; j >= 0; j --){
            str5.append(str4.get(j));
        }
        System.out.print(str5);
    }
}

这样就可以了。