接口

package com.lovely.string;/*** * @author echo lovely* 2020年6月9日下午6:44:31** 串的接口描述*/
public interface IString {public void clear();public boolean isEmpty(); public int length(); public char charAt(int i) throws Exception; // 读取并返回串中的第i个数据元素public IString subString(int begin, int end); // 返回位序号从begin到end-1的子串public void insert(int i, IString str) throws Exception; // 在第i个字符之前插入字串strpublic void delete(int begin, int end); // 删除位序号从begin到end-1的子串public IString concat(IString str); // 将str连接到字符串的后面public int compareTo(IString str); // 比较str和当前字符串的大小public int indexOf(IString str, int fromIndex) throws Exception; // 从位序号为begin的字符开始搜索与str相等的字串
}

查找增加…

package com.lovely.string;/*** @author echo lovely* 2020年6月9日下午6:55:32* 顺序串的实现*/
public class SeqString implements IString {private char[] strValue; // 字符数组存放传值private int curLen; // 当前串的长度public SeqString() {strValue = new char[0];curLen = 0;}// 以字符串常量构造串 本质是字符串 -> 字符数组public SeqString(String str) {strValue = str.toCharArray();curLen = strValue.length;}// 以字符数组构造串public SeqString(char[] ch) {strValue = new char[ch.length];for (int i = 0; i < ch.length; i++) {strValue[i] = ch[i];}curLen = ch.length;}public void clear() {strValue = new char[0];curLen = 0;}public boolean isEmpty() {return curLen == 0;}public int length() {return curLen;}public char charAt(int i) throws Exception {// 返回i的位置if (i < 0 || i >= curLen) throw new StringIndexOutOfBoundsException(i);return strValue[i];}// 将串的长度扩充为newCapacitypublic void allocate(int newCapacity) {if (newCapacity <= curLen) {System.err.print("扩充长度不能比当前长度小！");return;}char[] tmp = strValue;strValue = new char[newCapacity];// 剩下长度newCapacity - tmp.lengthfor (int i = 0; i < tmp.length; i++) {strValue[i] = tmp[i];}}public IString subString(int begin, int end) {// 字串截取if (begin < 0 || begin > end || end > curLen) throw new StringIndexOutOfBoundsException("参数不合法");char[] tmp = new char[end - begin];for (int i = begin; i < end; i ++) {tmp[i - begin] = strValue[i]; // 复制子串}return new SeqString(tmp);// 利用字符数组构造得到新的串}public void insert(int i, IString str) throws Exception {if (i < 0 || i > curLen)throw new StringIndexOutOfBoundsException("插入位置非法");int len = str.length();// 扩充字符数组长度int newCapacity = len + curLen;allocate(newCapacity);for (int j = curLen - 1; j >= i; j --) {// 把插入位置之后的数据 往后移strValue[j + len] = strValue[j];}for (int j = i; j < i + len; j ++) strValue[j] = str.charAt(j - i); // 插入curLen = newCapacity;}@Overridepublic void delete(int begin, int end) {if (begin < 0 || end > curLen || begin >= end) {throw new StringIndexOutOfBoundsException("参数非法");}/*don't konw...*/}@Overridepublic IString concat(IString str) {// str插入字符串的尾部try {insert(curLen, str);} catch (Exception e) {e.printStackTrace();}return new SeqString(strValue);}public int compareTo(IString str) {if (curLen > str.length())return 1;int n = Math.min(curLen, str.length());for (int i = 0; i < n; i ++) {try {if (strValue[i] > str.charAt(i)) return 1;if (strValue[i] < str.charAt(i))return -1;} catch (Exception e) {e.printStackTrace();}}return 0;}public int indexOf(IString str, int fromIndex) throws Exception {if (str.length() <= curLen && str != null && curLen > 0) {int i = fromIndex;int len = str.length();while (i <= curLen - len) { // 从主串的第i个元素开始比较for (int j = 0; j < len; j++) { // 比较模式串的元素if (str.charAt(j) != strValue[j + i]) {i++;break; // 跳出当前循环} else if (j == len - 1) { // len个字符全部匹配成功return i;}}}}return -1;}public void display() {for (int i = 0; i < length(); i ++) System.out.print(strValue[i] + "");System.out.println();} }

测试

package com.lovely.string;/*** * @author echo lovely* 2020年6月10日下午3:37:30*	* 串的测试demo*/public class TestSeqString {public static void main(String[] args) {	SeqString ss = new SeqString();try {ss.insert(0, new SeqString("abc"));char[] ch = {'d', 'e', 'f'}; // 插入串1下标ss.insert(1, new SeqString(ch));// 插入串的尾部ss.insert(ss.length(), new SeqString("ghi"));} catch (Exception e) {e.printStackTrace();}// 连接ss.concat(new SeqString("连接到串的尾部"));ss.display();// 比较int i = ss.compareTo(new SeqString("ghi"));System.out.println(i > 0 ? "前面的大" : "后面的大");// 截取IString sub = ss.subString(0, 3);System.out.println("前三个串: ");((SeqString)sub).display();try {// 下标System.out.println("def的下标 " + ss.indexOf(new SeqString("def"), 0));// 字符System.out.println("最后一个字符串 " + ss.charAt(ss.length() - 1));} catch (Exception e) {e.printStackTrace();}}}

adefbcghi连接到串的尾部
前面的大
前三个串: 
ade
def的下标 1
最后一个字符串 部