时间片轮转调度算法

#include<stdio.h>
#define MAX 10
struct task_struct
{
    char name[10];           /*进程名称*/
    int number;              /*进程编号*/
    float come_time;         /*到达时间*/
    float run_begin_time;     /*开始运行时间*/
    float run_time;          /*运行时间*/
    float run_end_time;      /*运行结束时间*/
    int priority;           /*优先级*/
    int run_flag;          /*调度标志*/
    int start_flag;     //是否为第一次开始调度
} tasks[MAX];
int counter; /*实际进程个数*/
int time_counter=0;
int poutput(); /*调度结果输出*/
int time();
int charge();//判断是否所有的进程都被执行过

void main()
{

    pinput();
    printf("时间片轮转算法。\n\n");
    time();
    poutput();
}

int time()
{
    float time_temp=0;
    int i;
    int j=0;
    int k=0;

    struct task_struct  copy_task[MAX];//备份
    for(i=0; i<counter; i++)
    {
        copy_task[j++]=tasks[i];//对进程的初始化信息备份
    }

    time_temp=tasks[0].come_time;
    while(charge())
    {
        for(i=0; i<counter; i++)
        {
            if(tasks[i].come_time>time_temp)
            {
                time_temp=tasks[i].come_time;
            }
            if(tasks[i].run_flag==0)//该进程还未结束
            {
                if(tasks[i].start_flag==0)  //该条件成立则说明，该进程是第一次执行，记录开始执行时间
                {
                    tasks[i].run_begin_time=time_temp;
                    tasks[i].start_flag=1;
                }
                if(tasks[i].run_time/time_counter>1)//至少有两倍的时间片未执行
                {
                    tasks[i].run_time=tasks[i].run_time-time_counter;
                    time_temp=time_temp+time_counter;
                }
                else if(tasks[i].run_time-time_counter==0)
                {
                    time_temp=time_temp+time_counter;
                    tasks[i].run_end_time=time_temp;
                    tasks[i].run_flag=1;
                    tasks[i].run_time=copy_task[i].run_time;
                }
                else//仅剩下不足一倍的时间片
                {
                    time_temp=time_temp+tasks[i].run_time;
                    tasks[i].run_end_time=time_temp;
                    tasks[i].run_flag=1;
                    tasks[i].run_time=copy_task[i].run_time;
                }
            }
        }
    }
}

int charge()//判断是否全部进程都执行完毕
{
    int k;
    int super_flag=0;//判断是否全部的进程都执行完毕
    for(k=0; k<counter; k++)
    {
        if(tasks[k].run_flag==0)
        {
            super_flag=1;
            return super_flag;
            break;
        }
        else
        {
            super_flag=0;
        }
    }
    return super_flag;
}

int pinput() /*进程参数输入*/
{
    int i;
    printf("please input the process counter:\n");
    scanf("%d",&counter);
    printf("please input the length of time:\n");
    scanf("%d",&time_counter);
    for(i=0; i<counter; i++)
    {
        printf("******************************************\n");
        printf("please input the process of %d th :\n",i+1);
        printf("please input the name:\n");
        scanf("%s",tasks[i].name);
        printf("please input the number:\n");
        scanf("%d",&tasks[i].number);
        printf("please input the come_time:\n");
        scanf("%f",&tasks[i].come_time);
        printf("please input the run_time:\n");
        scanf("%f",&tasks[i].run_time);
        printf("please input the priority:\n");
        scanf("%d",&tasks[i].priority);
        tasks[i].run_begin_time=0;
        tasks[i].run_end_time=0;
        tasks[i].run_flag=0;  //运行是否结束
        tasks[i].start_flag=0;//是否首次被执行
    }
    return 0;
}

int poutput() /*调度结果输出*/
{
    int i;
    float turn_round_time=0,f1,w=0;
    printf("进程名 进程号 到达时间 运行时间 开始时间 结束时间 优先级 周转时间\n");
    for(i=0; i<counter; i++)
    {
        f1=tasks[i].run_end_time-tasks[i].come_time;
        turn_round_time+=f1;
        printf("%s\t%d\t%5.3f\t%5.3f\t%5.3f\t %5.3f\t   %d\t  %5.3f\n",tasks[i].name,tasks[i].number,tasks[i].come_time,tasks[i].run_time,tasks[i].run_begin_time,tasks[i].run_end_time,tasks[i].priority,f1);
    }
    printf("average_turn_round_timer=%5.2f\n",turn_round_time/counter);
    return 0;
}