用c++实现多种进程调度算法

在操作系统中，进程调度算法用于决定哪个进程将获得处理器的控制权。以下是使用C++实现多种进程调度算法的示例：

1. 先来先服务（FCFS）调度算法

#include <iostream>
#include <queue>
#include <vector>
using namespace std;

struct Process {
    int pid;  // 进程ID
    int burst_time;  // 进程需要的CPU时间
    int arrival_time;  // 进程到达时间
    int waiting_time;  // 进程等待时间
    int turnaround_time;  // 进程周转时间
};

void fcfs(vector<Process> processes) {
    int n = processes.size();
    queue<Process> q;
    int current_time = 0;  // 当前时间
    for (int i = 0; i < n; i++) {
        while (!q.empty() && q.front().burst_time <= current_time) {
            Process p = q.front();
            q.pop();
            p.turnaround_time = current_time - p.arrival_time;
            p.waiting_time = p.turnaround_time - p.burst_time;
            cout << "进程 " << p.pid << " 周转时间为 " << p.turnaround_time
                 << " 等待时间为 " << p.waiting_time << endl;
        }
        q.push(processes[i]);
        current_time += processes[i].burst_time;
    }
    while (!q.empty()) {
        Process p = q.front();
        q.pop();
        p.turnaround_time = current_time - p.arrival_time;
        p.waiting_time = p.turnaround_time - p.burst_time;
        cout << "进程 " << p.pid << " 周转时间为 " << p.turnaround_time
             << " 等待时间为 " << p.waiting_time << endl;
        current_time += p.burst_time;
    }
}

int main() {
    vector<Process> processes = {{1, 10, 0, 0}, {2, 5, 1, 0}, {3, 8, 2, 0}};
    fcfs(processes);
    return 0;
}

2. 最短作业优先（SJF）调度算法

#include <algorithm>
#include <iostream>
#include <queue>
#include <vector>
using namespace std;

struct Process {
    int pid;  // 进程ID
    int burst_time;  // 进程需要的CPU时间
    int arrival_time;  // 进程到达时间
    int waiting_time;  // 进程等待时间
    int turnaround_time;  // 进程周转时间
};

bool compare(Process a, Process b) {
    return a.burst_time < b.burst_time;
}

void sjf(vector<Process> processes) {
    int n = processes.size();
    sort(processes.begin(), processes.end(), compare);
    queue<Process> q;
    int current_time = 0;  // 当前时间
    for (int i = 0; i < n; i++) {
        while (!q.empty() && q.front().burst_time <= current_time) {
            Process p = q.front();
            q.pop();
            p.turnaround_time = current_time - p.arrival_time;
            p.waiting_time = p.turnaround_time - p.burst_time;
            cout << "进程 " << p.pid << " 周转时间为 " << p.turnaround_time
                 << " 等待时间为 " << p.waiting_time << endl;
        }
        q.push(processes[i]);
        current_time += processes[i].burst_time;
    }
    while (!q.empty()) {
        Process p = q.front();
        q.pop();
        p.turnaround_time = current_time - p.arrival_time;
        p.waiting_time = p.turnaround_time - p.burst_time;
        cout << "进程 " << p.pid << " 周转时间为 " << p.turnaround_time
             << " 等待时间为 " << p.waiting_time << endl;
        current_time += p.burst_time;
    }
}

int main() {
    vector<Process> processes = {{1, 10, 0, 0}, {2, 5, 1, 0}, {3, 8, 2, 0}};
    sjf(processes);
    return 0;
}

3. 时间片轮转（RR）调度算法

#include <iostream>
#include <queue>
#include <vector>
using namespace std;

struct Process {
    int pid;  // 进程ID
    int burst_time;  // 进程需要的CPU时间
    int arrival_time;  // 进程到达时间
    int waiting_time;  // 进程等待时间
    int turnaround_time;  // 进程周转时间
};

void rr(vector<Process> processes, int time_slice) {
    int n = processes.size();
    queue<Process> q;
    int current_time = 0;  // 当前时间
    int i = 0;  // 当前进程的下标
    while (!q.empty() || i < n) {
        if (!q.empty()) {
            Process p = q.front();
            q.pop();
            int burst_time = min(p.burst_time, time_slice);
            p.burst_time -= burst_time;
            current_time += burst_time;
            for (; i < n && processes[i].arrival_time <= current_time; i++) {
                q.push(processes[i]);
            }
            if (p.burst_time == 0) {
                p.turnaround_time = current_time - p.arrival_time;
                p.waiting_time = p.turnaround_time - p.burst_time;
                cout << "进程 " << p.pid << " 周转时间为 " << p.turnaround_time
                     << " 等待时间为 " << p.waiting_time << endl;
            } else {
                q.push(p);
            }
        } else {
            q.push(processes[i]);
            current_time = processes[i].arrival_time;
            i++;
        }
    }
}

int main() {
    vector<Process> processes = {{1, 10, 0, 0}, {2, 5, 1, 0}, {3, 8, 2, 0}};
    rr(processes, 2);
    return 0;
}

以上是使用C++实现三种进程调度算法的示例。实现其他进程调度算法时，只需根据算法的特点和规则修改以上代码即可。