SRTF进程调度模拟(C++)

代码

#include <iostream>
#include <queue>
#include <set>
#include <fstream>

using namespace std;

enum type{arrival, finish};

struct event
{
    int time;
    type t;
    string procNo;
    int remainServT;
    bool firstArv;//到达事件是否为第一次
};

int main()
{
    auto cmp = [](event l, event r){return l.time < r.time;};
    multiset<event, decltype(cmp)> q(cmp);//按时间顺序排列的事件队列
    auto cmp2 = [](event l, event r){return l.remainServT > r.remainServT;};
    priority_queue<event, vector<event>, decltype(cmp2)> waitingProc(cmp2);//按剩余处理时间排列的阻塞进程队列

    //初始化事件队列
    ifstream in("data.txt");
    int procCnt;
    in >> procCnt;
    char No;
    int arrivalT, serviceT;
    event temp;
    temp.t = arrival;
    for(int i = 0; i < procCnt; ++i)
    {
        in >> No >> arrivalT >> serviceT;
        temp.time = arrivalT;
        temp.procNo = No;
        temp.remainServT = serviceT;
        temp.firstArv = true;
        q.insert(temp);
    }

    bool cpuWorking = false;
    event workingProc;//正在运行的进程
    int sysTime = 0;
    while(!q.empty())
    {
        event p = *q.begin();
        q.erase(q.begin());
        sysTime = p.time;
        if(p.t == arrival)//到达事件
        {
            int workingRemain = workingProc.time+workingProc.remainServT-sysTime;//当前进程的剩余时间
            bool wait = p.remainServT >= workingRemain;
            //workingRemain==0意味着当前进程已结束，但同时另一进程的到达事件在队列中先于此进程的结束事件，会引起错误，下为处理
            if(cpuWorking && wait && workingRemain==0)
            {
                waitingProc.push(p);
                continue;
            }
            else if(cpuWorking && wait)//等待
            {
                cout << sysTime << " : " + p.procNo + " arrive\n";
                event newWait = p;
                newWait.time = workingProc.time+workingProc.remainServT;
                newWait.firstArv = false;
                waitingProc.push(newWait);
            }
            else//抢占
            {
                if(cpuWorking)//处理被抢占的进程
                {
                    cout << sysTime << " : " + workingProc.procNo + " pause\n";
                    //删除原来的结束事件
                    auto it=q.begin();
                    while(it->t != finish)
                        it++;
                    q.erase(it);
                    //新的到达事件
                    event newWait = workingProc;
                    newWait.remainServT -= sysTime-workingProc.time;
                    newWait.firstArv = false;
                    waitingProc.push(newWait);
                }
                //运行此进程
                cpuWorking = true;
                workingProc = p;
                if(p.firstArv)
                    cout << sysTime << " : " + p.procNo + " arrive\n";
                cout << sysTime << " : " + p.procNo + " running\n";
                event f;
                f.time = p.time + p.remainServT;
                f.t = finish;
                f.procNo = p.procNo;
                q.insert(f);
            }
        }
        else//结束事件
        {
            cout << sysTime << " : " + p.procNo + " finish\n";
            if(!waitingProc.empty())
            {
                event select = waitingProc.top();
                waitingProc.pop();
                workingProc = select;
                if(select.firstArv)
                    cout << sysTime << " : " + select.procNo + " arrive\n";
                cout << sysTime << " : " + select.procNo + " running\n";
                event f;
                f.time = sysTime + select.remainServT;
                f.t = finish;
                f.procNo = select.procNo;
                q.insert(f);
            }
        }
    }
    return 0;
}

测试数据

data.txt
5
A 0 3
B 2 6
C 4 4
D 6 5
E 8 2