数据结构2_java---栈,括号匹配

 package Main;

 import java.util.Scanner;

 import javax.swing.text.html.HTMLDocument.HTMLReader.IsindexAction;

 /*栈操作*/
 public class Main{
         public int maxsize;
         public int top;
         private Object[] stackelem;
         //初始化
         public Main(int maxstack)
         {
             top = 0;
             this.maxsize = maxstack;
             stackelem = new Object[maxstack];
         }
         //将栈置空
         public void clear()
         {
             top = 0;
         }
         //判断栈是否为空
         public boolean isEmpty()
         {
             if(top==0)
                 return true;
             return false;
         }
         //入栈
         public void push(Object x) throws Exception
         {
             if(top==maxsize)
                 throw new Exception("the stack is enough");
             stackelem[top] = x;
             top++;
         }
         //从顶端开始输出所有栈内内容
         public void print() {
             for(int i=top-1;i>=0;i--)
             {
                 System.out.println(stackelem[i]);
             }
         }
         //出栈
         public Object pop() throws Exception
         {
             if(isEmpty())
                 throw new Exception("the stack is empty!");
             top--;
             return stackelem[top];
         }
     public static void main(String[] args) throws Exception {
         Main aStack = new Main(100);
         Scanner aScanner = new Scanner(System.in);
         String aString = aScanner.nextLine();
         char []a = new char[aString.length()];
         a = aString.toCharArray();
         Main bStack = new Main(100);
         for(int i=0;i<a.length;i++)
         {
             aStack.push(a[i]);
         }
         int flag=1;
         char pop;
         for(int i=0;i<a.length;i++)
         {
             pop = (char) aStack.pop();
             if(pop==')')
             {
                 bStack.push(pop);
             }else if(pop=='('&&bStack.isEmpty()){
                 flag = 0;

             }else if(pop=='(')
             {
                 bStack.pop();
             }
         }
         if (bStack.isEmpty()&&flag==1) {
             System.out.println("The String is right!");
         }else {
             System.out.println("the string is wrong!");
         }
         aStack.print();

     }
 }

使用java实现栈的操作，同时加入了括号匹配实现应用；

括号匹配：

（1）将所有输入的字符串压入栈中

（2）依次取出，遇到‘）’，则将其压入新栈中。

（3）遇到‘（’，则从新栈中取出与之匹配，判断最后栈是否为空；

（4）需要注意的是，第一个括号为反的情况，设置标志位flag用于判断。