进程的三种基本状态在代码里如何表示?

Question

进程的三种基本状态在代码里用c语言如何表示？

Answer 1

参考下进程的三种状态转换

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

#define Ready 0
#define Runnig 1
#define Block 2

typedef struct ProcessNode {
    int pid;  //进程标识符
    int status; //进程状态
    struct ProcessNode *next;
} ProcessNode;

typedef struct ListQueue {
    ProcessNode head;
    int process_num;
}ListQueue;


//创建一个进程节点
ProcessNode *create_ProcessNode(int pid, int status) {
    ProcessNode *node = (ProcessNode *)malloc(sizeof(ProcessNode));
    node->pid = pid;
    node->status = status;
    node->next = NULL;
    return node;
}

//初始化一个队列
ListQueue *init_queue() {
    ListQueue *que = (ListQueue *)malloc(sizeof(ListQueue));
    que->head.next = NULL;
    que->process_num = 0;
    return que;
}

//判空
int empty(ListQueue *que) {
    if(que->process_num == 0) return 1;
    else return 0;
}

//入队
int push(ListQueue *que, int pid, int status) {
    if(que == NULL) return 0;
    ProcessNode *node = create_ProcessNode(pid, status);
    ProcessNode *p = &(que->head);
    while(p->next) {
        p = p->next;
    }
    node->next = p->next;
    p->next = node;
    que->process_num++;
    return 1;
}

//出队
int pop(ListQueue *que) {
    if(empty(que))return -1;
    ProcessNode *p = &(que->head), *q;
    int pid;
    q = p->next;
    p->next = q->next;
    pid = q->pid;
    free(q);
    que->process_num--;
    return pid;
}

//输出
void output(ListQueue *que) {
    ProcessNode *p = que->head.next;
    while(p) {
        printf("%d ", p->pid);
        p = p->next;
    }
    printf("\n");
    return ;
}

//清空
void clear_ListQueue(ListQueue *que) {
    if(que == NULL) return ;
    ProcessNode *p, *q;
    p = que->head.next;
    while(p) {
        q = p->next;
        free(p);
        p = q;
    }
    free(que);
    return ;
}

int main() {
    ListQueue *ready_queue = init_queue();   
    ListQueue *runnig_queue = init_queue();
    ListQueue *block_queue = init_queue();
    int n;
    printf("------------------------------进程初始创建------------------------------\n");
    printf("请输入进程数目：");
    scanf("%d", &n);
    printf("输入%d个进程的标识符：\n", n);
    int pid;
    for(int i = 1; i <= n; i++) {
        scanf("%d", &pid);
        getchar();
        int status = Ready;
        push(ready_queue, pid, status);
    }
    printf("进程已创建！\n");
    printf("[就绪队列]:");
    output(ready_queue);
    printf("[执行队列]:");
    output(runnig_queue);
    printf("[阻塞队列]:");
    output(block_queue);
    printf("------------------------------进程状态转换------------------------------\n");
    printf("说明：按P-->进程调度    按I-->I/O或其他事件发生   按O-->I/O或其他事件完成   按E-->时间片用完   \n");
   
    while(1) {
        printf("\n输入操作: ");
        char c;
        scanf("%c", &c);
        getchar();
        int pid;
        if(c == 'P') {
            pid = pop(ready_queue);
            if(pid == -1) {
                printf("就绪队列无进程！\n");
                continue;
            }
            printf("进程 %d 由就绪态进入执行态！\n", pid);
            push(runnig_queue, pid, Runnig);
        } else if(c == 'I') {
            pid = pop(runnig_queue);
            if(pid == -1) {
                printf("执行队列无进程！");
                continue;
            }
            printf("进程 %d 由执行态进入阻塞态！\n", pid);
            push(block_queue, pid, Block);
        } else if(c == 'O'){
            pid = pop(block_queue);
            if(pid == -1) {
                printf("阻塞队列无进程！\n");
                continue;
            }
            printf("进程 %d 由阻塞态进入就绪态！\n", pid);
            push(ready_queue, pid, Block);
        } else if(c == 'E'){
            pid = pop(runnig_queue);
            if(pid == -1) {
                printf("执行队列无进程！\n");
                continue;
            }
            printf("进程 %d 由执行态进入就绪态！\n", pid);
            push(ready_queue, pid, Block);
        } else {
            printf("操作错误，请看说明！");
        }
        printf("[就绪队列]:");
        output(ready_queue);
        printf("[执行队列]:");
        output(runnig_queue);
        printf("[阻塞队列]:");
        output(block_queue);
    }
    clear_ListQueue(ready_queue);
    clear_ListQueue(runnig_queue);
    clear_ListQueue(block_queue);
    return 0;
}