使用C语言完成进程的创建、终止、阻塞、唤醒、通信和实现先来先服务调度算法

进程的创建：

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>

int main() {
    pid_t pid;
    pid = fork();
    if (pid < 0) {
        printf("Error: fork failed.\n");
        exit(1);
    } else if (pid == 0) {
        // 子进程
        printf("This is child process.\n");
        exit(0);
    } else {
        // 父进程
        printf("This is parent process.\n");
        wait(NULL); // 等待子进程结束
        exit(0);
    }
}

进程的终止：

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>

int main() {
    pid_t pid;
    pid = fork();
    if (pid < 0) {
        printf("Error: fork failed.\n");
        exit(1);
    } else if (pid == 0) {
        // 子进程
        printf("This is child process.\n");
        exit(0);
    } else {
        // 父进程
        printf("This is parent process.\n");
        wait(NULL); // 等待子进程结束
        printf("Child process has terminated.\n");
        exit(0);
    }
}

进程的阻塞和唤醒：

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>

int main() {
    pid_t pid;
    int status;
    pid = fork();
    if (pid < 0) {
        printf("Error: fork failed.\n");
        exit(1);
    } else if (pid == 0) {
        // 子进程
        printf("This is child process.\n");
        sleep(5); // 子进程休眠5秒
        exit(0);
    } else {
        // 父进程
        printf("This is parent process.\n");
        wait(&status); // 等待子进程结束
        if (WIFEXITED(status)) {
            printf("Child process has terminated.\n");
        }
        exit(0);
    }
}

进程的通信：

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
int main() {
    int fd[2];
    pid_t pid;
    char buf[256];
    if (pipe(fd) < 0) {
        printf("Error: pipe failed.\n");
        exit(1);
    }
    pid = fork();
    if (pid < 0) {
        printf("Error: fork failed.\n");
        exit(1);
    } else if (pid == 0) {
        // 子进程
        close(fd[0]); // 关闭读端
        write(fd[1], "Hello, parent process!", 23);
        exit(0);
    } else {
        // 父进程
        close(fd[1]); // 关闭写端
        read(fd[0], buf, 23);
        printf("%s\n", buf);
        wait(NULL); // 等待子进程结束
        exit(0);
    }
}

先来先服务调度算法：

#include <stdio.h>
#include <stdlib.h>

struct Process {
    int id; // 进程ID
    int arrive_time; // 到达时间
    int service_time; // 服务时间
    int start_time; // 开始时间
    int finish_time; // 完成时间
    int turnaround_time; // 周转时间
    int waiting_time; // 等待时间
};

int main() {
    int n, i, j;
    float avg_turnaround_time = 0, avg_waiting_time = 0;
    printf("Enter the number of processes: ");
    scanf("%d", &n);
    struct Process p[n], temp;
    for (i = 0; i < n; i++) {
        printf("Enter the arrival time and service time of process %d: ", i + 1);
        scanf("%d%d", &p[i].arrive_time, &p[i].service_time);
        p[i].id = i + 1;
    }
    // 按到达时间排序
    for (i = 0; i < n - 1; i++) {
        for (j = 0; j < n - i - 1; j++) {
            if (p[j].arrive_time > p[j + 1].arrive_time) {
                temp = p[j];
                p[j] = p[j + 1];
                p[j + 1] = temp;
            }
        }
    }
    // 计算开始时间、完成时间、周转时间和等待时间
    for (i = 0; i < n; i++) {
        if (i == 0) {
            p[i].start_time = p[i].arrive_time;
        } else {
            p[i].start_time = p[i - 1].finish_time;
        }
        p[i].finish_time = p[i].start_time + p[i].service_time;
        p[i].turnaround_time = p[i].finish_time - p[i].arrive_time;
        p[i].waiting_time = p[i].turnaround_time - p[i].service_time;
        avg_turnaround_time += p[i].turnaround_time;
        avg_waiting_time += p[i].waiting_time;
    }
    // 输出结果
    printf("Process\tArrival Time\tService Time\tStart Time\tFinish Time\tTurnaround Time\tWaiting Time\n");
    for (i = 0; i < n; i++) {
        printf("%d\t%d\t\t%d\t\t%d\t\t%d\t\t%d\t\t\t%d\n", p[i].id, p[i].arrive_time, p[i].service_time, p[i].start_time, p[i].finish_time, p[i].turnaround_time, p[i].waiting_time);
    }
    avg_turnaround_time /= n;
    avg_waiting_time /= n;
    printf("Average turnaround time: %.2f\n", avg_turnaround_time);
    printf("Average waiting time: %.2f\n", avg_waiting_time);
    return 0;
}