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twoqueue_onestack.cpp

#include <iostream>
#include <queue>
#include <string>
#include <exception>

using namespace std;

queue<int> qu1, qu2;

enum : int { QUEUE_MIN = 0 ,QUEUE_MAX = 10};

void push(int val)
{
        if(qu1.size() == QUEUE_MAX)
        {
                throw "stack overflow";
        }
        qu1.push(val);
        std::cout << val << " pushed" << std::endl;
}
int pop()
{
        int ret;
        if(qu1.size() == QUEUE_MIN)
        {
                throw "stack underflow";
        }
        for(size_t i = qu1.size(); i > 1; --i)
        {
                qu2.push( qu1.front() );
                qu1.pop();
        }
        ret = qu1.front();
        qu1.pop();

        for(size_t i = qu2.size(); i > 0; --i)
        {
                qu1.push( qu2.front() );
                qu2.pop();
        }
        return ret;
}

int main()
{
        int val, option;
        try{
        while(true)
        {
                std::cout << "1.push 2.pop 3.end" << std::endl;
                std::cin >> option;
                switch(option)
                {
                        case 1:
                                std::cout << "push : ";
                                std::cin >> val;
                                push(val);
                                break;
                        case 2:
                                std::cout << "pop : " << pop() << std::endl;
                                break;
                        case 3:
                                return 0;
                                break;
                        default:
                                std::cout << "no options" << std::endl;
                }
        }
        }catch(const char * e) {
                std::cerr << e << std::endl;
        }

}

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