Java算法之串的简单处理

public class 串的简单处理 {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);
    String string = scanner.nextLine();
    Vector<Character> vector = new Vector<Character>();
    for (int i = 0; i < string.length(); i++) {
      vector.add(string.charAt(i));
    }
    try {
      int index = 0;
      while (index < vector.size()) {
        //判断第一个是否为小写的英文字符，是的话进行操作
        if (index == 0 && vector.elementAt(index) >= 'a'
            && vector.elementAt(index) <= 'z') {
          //Replaces the element at the specified position in this Vector with the specified element
          vector.set(index,(char) (vector.elementAt(index) - ('a' - 'A')));
        } else if (vector.elementAt(index - 1) == ' '&& vector.elementAt(index) == ' ') {
          //处理有多个空格的可能
          vector.remove(index);
          index--;
        } else if (vector.elementAt(index - 1) == ' '
            && (vector.elementAt(index) >= 'a' && vector
                .elementAt(index) <= 'z')) {
          //判断是空格后边的字符
          vector.set(index,
              (char) (vector.elementAt(index) - ('a' - 'A')));
        } else if ((vector.elementAt(index) >= 'a' && vector
            .elementAt(index) <= 'z')
            && (vector.elementAt(index - 1) >= '0' && vector
                .elementAt(index - 1) <= '9')) {
          vector.add(index, '_');
          index++;
        } else if ((vector.elementAt(index - 1) >= 'a' && vector
            .elementAt(index - 1) <= 'z')
            && (vector.elementAt(index) >= '0' && vector
                .elementAt(index) <= '9')) {
          //判断的是数字
          vector.add(index, '_');
          index++;
        }
        index++;
      }
      for (int i = 0; i < vector.size(); i++) {
        System.out.print(vector.elementAt(i));
      }
      System.out.println();
    } catch (ArrayIndexOutOfBoundsException e) {
    }
  }
}

public class SimpleString {
  // 打印字符串的函数
  public static void print(String[] s) {
    for (int i = 0; i < s.length - 1; i++) {
      System.out.print(s[i] + " ");
    }
    System.out.println(s[s.length - 1]);
  }
  public static void main(String[] args) {
    Scanner scan = new Scanner(System.in);
    String s = scan.nextLine();
    String[] ss = s.split("[\\s]+"); // 根据正则表达式，删除一个或多个空格,将字符串保存为字符数组
    for (int i = 0; i < ss.length; i++) {
      // 将每一个字符数组的首字母改为大写
      String up = ("" + ss[i].charAt(0)).toUpperCase(); // 大写
      StringBuffer sb = new StringBuffer(ss[i]);
      ss[i] = sb.replace(0, 1, up).toString();
      // 上边已经把字符串数组的首字母该为大写，然后对更改后的字符数组判断是否有数字
      Matcher m = Pattern.compile("\\d+").matcher(ss[i]);// 0-9出现一次或多次
      while (m.find()) {
        // m.group()：Returns the input subsequence matched by the previous match
        String num = new String(m.group());
        String num2 = num;
        num2 = "_" + num + "_"; // 数字前后都添加"_"
        ss[i] = ss[i].replace(num, num2);
        if (ss[i].startsWith("_")) { // 去头"_"
          ss[i] = ss[i].substring(1);
        }
        if (ss[i].endsWith("_")) { // 去尾"_"
          ss[i] = ss[i].substring(0, ss[i].length() - 1);
        }
      }
    }
    print(ss);
  }
}