数据结构变量字符串类（JAVA）

package Chapter3;

import java.io.Serializable;

public class MyStringBuffer implements Serializable {
    private char[] value;   //字符数组，私有成员变量
    private int n;          //串长度

    
    public MyStringBuffer(int capacity){
        this.value=new char[capacity];
        this.n=0;
    }
    
    public MyStringBuffer(){
        this(16);
    }
    
    public MyStringBuffer(String s){
        this(s.length()+16);
        this.n=s.length();
        for (int i=0; i this.n){
            i=this.n;
        }
        return this.value[i];
    }
    
    public void setCharAt(int i, char ch){
        if (i < 0){
            i=0;
        }
        else if (i > this.n){
            i=this.n;
        }
        this.value[i]=ch;
    }

    
    public synchronized MyStringBuffer insert(int i, String s){
        if (this.n==0 && i==0 || this.n>0 && i>=0 && i<=this.n){
            if (s==null){
                s="";
            }
            char[] temp=this.value;
            //若数组空间不足，则扩充
            if (this.value.length =i; j--){
                this.value[j + s.length()]=temp[j];
            }
            for (int j=0; j