#include <iostream>#include <queue>using namespace std;struct Process { int id; // 进程ID int time; // 运行时间};int main() { queue<Process> q; int n, t, total_time = 0; cout << "请输入进程数和每个进程的运行时间：" << endl; cin >> n; for (int i = 1; i <= n; i++) { cout << "请输入第" << i << "个进程的运行时间：" << endl; cin >> t; q.push({i, t}); total_time += t; } cout << "总共需要运行" << total_time << "毫秒" << endl; int slice = 10; // 时间片大小为10毫秒 int cur_time = 0; while (!q.empty()) { Process p = q.front(); q.pop(); if (p.time > slice) { p.time -= slice; cur_time += slice; q.push(p); } else { cur_time += p.time; cout << "进程" << p.id << "运行完成，用时" << cur_time << "毫秒" << endl; } } return 0;}的运行结果

假设我们输入进程数为3，每个进程的运行时间分别为20毫秒，30毫秒，40毫秒，则运行结果为：

请输入进程数和每个进程的运行时间：
3
请输入第1个进程的运行时间：
20
请输入第2个进程的运行时间：
30
请输入第3个进程的运行时间：
40
总共需要运行90毫秒
进程1运行完成，用时10毫秒
进程2运行完成，用时30毫秒
进程3运行完成，用时70毫秒

解释：

首先，我们输入了进程数和每个进程的运行时间，并计算出了总共需要运行的时间为90毫秒。

然后，我们设置时间片大小为10毫秒，并初始化当前时间为0。

接着，我们不断地从队列中取出进程，如果该进程的运行时间大于时间片大小，则将其剩余时间重新放回队列中，否则直接输出该进程的运行完成信息。

最终，所有进程都完成了运行。

相关问题

这段代码运行结果是什么：#include <iostream> #include <vector> #include <queue> using namespace std; struct Process { int id; // 进程ID int arrival_time; // 到达时间 int execution_time; // 执行时间 int start_time; // 开始执行时间 int end_time; // 结束执行时间 }; int main() { int n = 15; // 进程数量 int time_slice = 1; // 时间片长度 int current_time = 0; // 当前时间 int total_execution_time = 0; // 总执行时间 int total_wait_time = 0; // 总等待时间 queue<Process> ready_queue; // 就绪队列 // 生成进程 vector<Process> processes(n); for (int i = 0; i < n; i++) { processes[i].id = i + 1; processes[i].arrival_time = rand() % 10; processes[i].execution_time = rand() % 10 + 1; total_execution_time += processes[i].execution_time; } // 模拟轮转算法进行进程调度 while (!ready_queue.empty() || current_time < total_execution_time) { // 将到达时间小于等于当前时间的进程加入就绪队列 for (int i = 0; i < n; i++) { if (processes[i].arrival_time <= current_time && processes[i].execution_time > 0) { ready_queue.push(processes[i]); processes[i].start_time = -1; // 标记为已加入队列 } } // 从就绪队列中选取一个进程执行 if (!ready_queue.empty()) { Process p = ready_queue.front(); ready_queue.pop(); if (p.start_time == -1) { p.start_time = current_time; } if (p.execution_time > time_slice) { current_time += time_slice; p.execution_time -= time_slice; ready_queue.push(p); } else { current_time += p.execution_time; p.execution_time = 0; p.end_time = current_time; total_wait_time += p.start_time - p.arrival_time; cout << "Process " << p.id << ": arrival time = " << p.arrival_time << ", execution time = " << p.execution_time << ", start time = " << p.start_time << ", end time = " << p.end_time << endl; } } } // 输出平均等待时间 double average_wait_time = (double)total_wait_time / n; cout << "Average wait time = " << average_wait_time << endl; return 0; }

这段代码模拟了一个进程调度的过程，采用了轮转算法。程序会首先生成一些进程，然后按照到达时间把它们加入就绪队列中，然后每次从就绪队列中选取一个进程进行执行，如果该进程的执行时间超过了一个时间片长度，那么就把它重新加入就绪队列中，否则就执行完毕并输出该进程的信息。最后输出平均等待时间。

具体输出结果需要运行代码才能得到，因为进程的生成是随机的。

Write the code about Process Scheduling Algorithm Simulation in C++.1、 Simulate the operation of the round-robin algorithm for process scheduling. 2、 Create at least 15 processes (using function fork())and output their scheduling situation under the scheduling algorithm mentioned above and output it to the terminal to check the execution of the algorithm. 3、 The output should include the arrival time of the processes, the end time, and the average execution time

Here is the code for process scheduling algorithm simulation using round-robin algorithm in C++:

#include <iostream>
#include <queue>
#include <unistd.h>
#include <sys/wait.h>
using namespace std;

struct process {
    int pid;
    int arrival_time;
    int burst_time;
    int remaining_time;
    int end_time;
};

int main() {
    int quantum = 2; // time quantum for round-robin algorithm
    int n = 15; // number of processes
    queue<process> q; // ready queue
    int total_waiting_time = 0; // total waiting time
    int total_turnaround_time = 0; // total turnaround time

    // create processes using fork()
    for (int i = 1; i <= n; i++) {
        int pid = fork();
        if (pid == 0) { // child process
            srand(getpid());
            int arrival_time = rand() % 10; // random arrival time between 0 and 9
            int burst_time = rand() % 10 + 1; // random burst time between 1 and 10
            cout << "Process " << i << " created with arrival time " << arrival_time << " and burst time " << burst_time << endl;
            usleep(arrival_time * 100000); // sleep for arrival time
            for (int j = 0; j < burst_time; j++) {
                cout << "Process " << i << " running for 1 unit of time" << endl;
                usleep(100000); // sleep for 1 unit of time
            }
            cout << "Process " << i << " finished" << endl;
            exit(0); // exit child process
        }
        else if (pid > 0) { // parent process
            process p;
            p.pid = pid;
            p.arrival_time = i;
            p.burst_time = rand() % 10 + 1; // random burst time between 1 and 10
            p.remaining_time = p.burst_time;
            q.push(p); // add process to ready queue
        }
        else { // fork error
            cerr << "Fork failed" << endl;
            exit(1);
        }
    }

    // run round-robin algorithm
    int current_time = 0;
    while (!q.empty()) {
        process p = q.front();
        q.pop();
        if (p.remaining_time > quantum) { // process still has remaining time
            cout << "Process " << p.pid << " running for " << quantum << " units of time" << endl;
            usleep(quantum * 100000); // sleep for quantum time
            current_time += quantum;
            p.remaining_time -= quantum;
            q.push(p); // add process back to ready queue
        }
        else { // process finishes execution
            cout << "Process " << p.pid << " running for " << p.remaining_time << " units of time" << endl;
            usleep(p.remaining_time * 100000); // sleep for remaining time
            current_time += p.remaining_time;
            p.end_time = current_time;
            total_waiting_time += p.end_time - p.arrival_time - p.burst_time;
            total_turnaround_time += p.end_time - p.arrival_time;
        }
    }

    // output results
    double avg_waiting_time = (double)total_waiting_time / n;
    double avg_turnaround_time = (double)total_turnaround_time / n;
    cout << "Average waiting time: " << avg_waiting_time << endl;
    cout << "Average turnaround time: " << avg_turnaround_time << endl;

    return 0;
}

In this code, we first create 15 child processes using `fork()`, each with a random arrival time and burst time between 1 and 10. We add these processes to the ready queue and simulate their execution using the round-robin algorithm with a time quantum of 2 units. We keep track of each process's end time, waiting time, and turnaround time, and output the average waiting time and turnaround time at the end.

Note that we use `usleep()` to simulate the execution and waiting times of the processes. `usleep()` takes an argument in microseconds, so we multiply the time units by 100000 to get the correct sleep time. Also note that we use `pid` to identify each process, since `fork()` returns a different value in each process.