<数据结构>stack & queue

stack：先进后出

queue：先进先出

c++STL提供的函数：

stack：

empty()

pop() //删除栈首元素,返回void

push()

top() //返回栈首元素

swap(stack s) //交换两个栈元素

size() //元素个数

 

queue:

empty()

pop() //删除front()返回的元素，即队列中最老的元素

push()

front() //返回队列中最老的元素

back() //返回最新元素

size()

swap()

 

使用：

#include<iostream>#include<stack>#include<queue>using namespace std;int NUM=9; template<class T>struct node{T val;node *next;};template<class T>class MyStack{private:node<T> *top;public:MyStack(){top=NULL;};~MyStack(){node<T> *temp = top;while(temp!=NULL){cout<<"delete:"<<temp->val<<endl;node<T> *t = temp;temp =temp->next;delete t;}};void push(const T &it){node<T> *temp = new node<T>();temp->val = it;if(top==NULL){//元素插入到链表首，符合先进后出的思想temp->next = NULL;top = temp;}else{temp->next = top;top = temp;}};void pop(){if(top == NULL){cerr<<"empty stack."<<endl;exit(-1);}node<T> *temp = top;top = temp->next;delete temp;};T gettop()const{if(top==NULL){cerr<<"empty stack."<<endl;exit(-1);}return top->val;};int size()const{int count=0;node<T> *temp = top;while(temp!=NULL){count ++;temp = temp->next;}return count;};bool empty()const{return (top == NULL)?true:false;};friend ostream& operator << <T>(ostream& os,MyStack<T>& s);//带模板的友元函数声明};template<class T>ostream& operator <<(ostream& os,MyStack<T> &s){node<T> *temp = s.top;while(temp!=NULL){os<<temp->val<<" ";temp = temp->next;}return os;};int main(){//mystackcout<<"-----mystack-----"<<endl;MyStack<int> ms;if(ms.empty()){for(int i=0;i<NUM;i++) ms.push(i);}cout<<ms<<endl;cout<<"size:"<<ms.size()<<endl;ms.pop();cout<<"top="<<ms.gettop()<<endl;/*STL stack**/cout<<"\n-----STL stack-------"<<endl;stack<int> s,s2;if(s.empty())for(int i =0;i<NUM;i++){s.push(i);//s :0-8s2.push(8-i);}s2.push(9);//S2 0-9//s.pop();//删除topcout<<"s.size:"<<s.size()<<endl;while(!s2.empty()){cout<<s2.top()<<' ';s2.pop();}cout<<endl;//s.emplace(4);s.swap(s2);//交换s与s2while(!s2.empty()){cout<<s2.top()<<' ';s2.pop();}/*队列queue*先进先出：q.front()返回队列最前端的元素 q.pop()删除对前端元素*/cout<<"\n------STL queue------"<<endl;queue<int> q,q2;if(q.empty()){for(int i =0;i<NUM;i++){q.push(i);//s :0-8//q2.push(8-i);}}cout<<q.size()<<endl;cout<<q.front()<<endl;//队列最前端元素(即最早入队列的元素)cout<<q.back()<<endl;//队列末尾元素(最晚进队列元素)//q.pop();//q2.push(9);//q.swap(q2);cout<<endl;}