用两个栈实现一个队列(C++)

#include "malloc.h"
#include "iostream"

using namespace std;

#define STACKINCREMENT 10
#define STACK_INIT_SIZE 10

class stack {
public :
   int * base;
   int * top;
   int stacksize;

   bool initStack()
   {
       base = (int *)malloc(STACK_INIT_SIZE * sizeof(int));
       if(!base) return false; /*分配空间失败*/
       top = base;
       stacksize = STACK_INIT_SIZE;
       return true;           /*初始化栈成功*/
   }

   bool Push(int e) {
       if(top - base >= stacksize){
                   /*栈满，追加空间*/
           base = (int *)realloc(base, (stacksize +
           STACKINCREMENT)*sizeof(int));
           if(!base) return false; /*存储分配失败*/
           top = base + stacksize;
           stacksize = stacksize + STACKINCREMENT; /*设置栈的最大容量*/
           }
           *top = e; /*放入数据*/
           top++;
           return true;
   }

   bool Pop(int &e) {
       if(top == base) return false; /*栈空，非法操作*/
       e = *--top;
       return true;
   }

   ~stack() {
       if (base != NULL) {
           free(base);               /*析构函数，释放堆内存空间*/
       }
   }
};

class queue {
stack s1, s2; /*定义两个栈s1和s2，用它们实现一个队列*/

public :
   bool initQueue() {
       if (s1.initStack() && s2.initStack() ) {   /*初始化队列，调用stack的初始化*/
           return true;
       }
       return false;
   }

   bool EnQueue(int x) {
       if (s1.Push(x)) {
           return true;       /*入队列，将x压入栈s1*/
       }
       return false;
   }

   bool DeQueue(int &x) {
       int e;
       if (s2.base == s2.top) {
           /*栈s2为空的情况*/
           if (s1.top == s1.base) {
               return false;
           } else {
               while (s1.Pop(e)) {
                   s2.Push(e);
               }
           }
       }
       s2.Pop(x);       /*出队列，从栈s2中取出数据*/
       return true;
   }

   bool IsEmptyQueue() {
       if (s1.base == s1.top && s2.base == s2.top) {
           return true;   /*队列为空*/
       } else {
           return false; /*队列不为空*/
       }
   }

   int getCount() {
       return s1.top - s1.base + s2.top - s2.base; /*计算两个栈当前容量之和*/
   }
};

int main() {
   int i, x=0, e;
   queue q;
   q.initQueue();       /*初始化一个队列*/

   for (i=0; i<10; i++) {
       q.EnQueue(x);           /*入队列操作，0~9*/
       x++;
   }
   for (i=0; i<5; i++) {
       if (q.DeQueue(e)) {
           cout<<e<<" ";   /*出队列操作，连续出队列5次，并打印在屏幕上*/
       }
   }
/*输出当前队列中元素的个数*/
   cout << "\nThe number of elements in the queue is " <<q.getCount() <<endl;
   for (i=0; i<10; i++) {
       q.EnQueue(x);             /*入队列操作，10~19*/
       x++;
   }
   for (i=0; i<15; i++) {
       if (q.DeQueue(e)) {       /*出队列操作，连续出队列15次，并打印在屏幕上*/
           cout<<e<<" ";
       }
   }
   /*输出当前队列中元素的个数*/
   cout << "\nThe number of elements in the queue is " <<q.getCount() <<endl;
   /*打印当前队列是否为空*/
   if (q.IsEmptyQueue()) {
       cout << "The queue is empty" << endl;
   } else {
       cout << "The queue is NOT empty" << endl;
   }
   getchar();
}

用两个栈实现一个队列(C++)

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