1、先来先服务算法（FCFS）First Come First Service
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这是一种比较简单的磁盘调度算法。它根据进程请求访问磁盘的先后次序进行调度。此算法的优点是公平、简单，且每个进程的请求都能依次得到处理，不会出现某一进程的请求长期得不到满足的情况。此算法由于未对寻道进行优化，在对磁盘的访问请求比较多的情况下，此算法将降低设备服务的吞吐量，致使平均寻道时间可能较长，但各进程得到服务的响应时间的变化幅度较小。
先来先服务 （125）86.147.91.177.94.150.102.175.130
[java] view plain copy print?
没java的 发段源代码给你 有兴趣自己慢慢理解
#include time.h
#include dos.h
#include math.h
#include conio.h
#include stdio.h
#include stdlib.h
#include time.h
#include graphics.h
#define ESC 0x1b
#define ENTER 0x0d
#define TRUE 1
#define FALSE 0
/*每隔TIME秒就变换一次优先级*/
#define TIME 5
/*数据结构*/
/****************************************************************/
enum _Status/*进程状态枚举*/
{
READY =0,/*就绪*/
RUN,/*执行中*/
SUSPEND,/*挂起*/
};
typedef enum _Status Status;
/****************************************************************/
struct _Pcb/*进程结构*/
{
int PID;/*进程ID，ID为负数的进程为系统后备队列的作业*/
int Time;/*进程运行需要的时间*/
int Prior;/*进程的优先级，越大越优先*/
Status Sts;/*状态*/
struct _Pcb *Next;/*指向本进程队列中下个进程的PCB*/
};
typedef struct _Pcb PCB;
/****************************************************************/
struct _Batch/*多道处理中的道结构*/
{
PCB *pcb;/*该道当前正在处理的进程*/
struct _Batch *Next;/*下一道*/
};
typedef struct _Batch Batch;
/****************************************************************/
/*多道系统相关全局变量*/
PCB *ProcQueue = NULL;/*进程链表，按优先级从大到小排列*/
Batch *BatchQueue = NULL;/*系统多道链表*/
/****************************************************************/
/*动态优先权抢占式调度算法及相关函数声明*/
/****************************************************************/
int InitBatchs(int n);/*初始化多道系统，n为道数*/
int InsertProc(int prior, int time);/*向进程链表中按优先级大小插入一个新进程*/
int InsertIDLE();/*向进程队列中加入后备进程，当系统空闲时将被调入*/
int SortProcQueue();/*将进程链表按优先级从大到小排列*/
int AddBatch();/*增加系统道数*/
int DeleteBatch();/*减少系统道数*/
int UnSuspendProc(int id);/*解除ID为id的进程的挂起状态*/
int UpdateBatchs();/*多道系统根据进程链表进行更新，并将执行完毕的进程删除*/
int PassSeconds(int n);/*系统经过n秒后计算数据并进行优先级调度*/
/****************************************************************/
/*各函数的定义*/
/****************************************************************/
int InitBatchs(int n)
{
int i;
for (i=0; in; ++i)
{
AddBatch();
}
return (UpdateBatchs());
}
int InsertProc(int prior, int time)
{
static int sysid = 0;/*该系统已经加入过多少进程，此值将是新进程的ID*/
PCB *last,*now,*pcb;
pcb = (PCB*)malloc(sizeof(PCB));
if (pcb == NULL) return FALSE;
pcb-Prior = prior;
pcb-Time = time;
pcb-PID = (++sysid);
pcb-Sts = READY;
if (ProcQueue == NULL)/*如果进程队列为空*/
{
ProcQueue = pcb;
pcb-Next = NULL;
return TRUE;
}
last = ProcQueue;
now = last-Next;
if (pcb-Prior last-Prior)/*pcb将排在队头*/
{
pcb-Next = ProcQueue;
ProcQueue = pcb;
return TRUE;
}
while ((now != NULL) (pcb-Prior now-Prior))/*寻找插入位置*/
{
last = now;
now = last-Next;
}
last-Next = pcb;
pcb-Next = now;
return TRUE;
}
int InsertIDLE()
{
PCB *now = ProcQueue;
PCB *idle = (PCB*)malloc(sizeof(PCB));
if (idle == NULL) return FALSE;
idle-PID = -1;
idle-Prior = -1;
idle-Sts = SUSPEND;
idle-Time = -1;
idle-Next = NULL;
if (ProcQueue == NULL)
{
ProcQueue = idle;
return TRUE;
}
while(now-Next != NULL)
{
now = now-Next;
}
now-Next = idle;
return TRUE;
}
int SortProcQueue()
{ /*冒泡排序*/
PCB *last, *now;
int b = FALSE;/*上次遍历是否无交换产生*/
if (ProcQueue==NULL || ProcQueue-Next==NULL)/*如果链表中无进程或只有一个进程*/
return FALSE;
while (!b)
{
b = TRUE;
last=ProcQueue;
now=last-Next;
if (last-Prior now-Prior)
{
ProcQueue = now;
last-Next = now-Next;
now-Next = last;
b = FALSE;
last = ProcQueue;
now = last-Next;
}
while (now-Next!=NULL)
{
if ((now-Prior)(now-Next-Prior))
{
last-Next = now-Next;
now-Next = now-Next-Next;
last-Next-Next = now;
b = FALSE;
}
else
last = last-Next;
now = last-Next;
}
}
return TRUE;
}
int AddBatch()
{
Batch *bt = (Batch*)malloc(sizeof(Batch));
if (bt==NULL) return FALSE;
bt-Next = BatchQueue;
BatchQueue = bt;
bt-pcb = NULL;
return (InsertIDLE());
}
int DeleteBatch()
{
Batch *bt = BatchQueue;
PCB *last, *now;
if (BatchQueue==NULL || BatchQueue-Next==NULL)/*如果只剩最后一道则不删除*/
return FALSE;
if (ProcQueue==NULL || ProcQueue-Next==NULL)/*如果只有最后一个后备空闲进程*/
return FALSE;/**/
last = ProcQueue;
now = last-Next;
while (now-Next != NULL)/*查找到最后一个进程，该进程必定是后备空闲进程*/
{
last = now;
now = last-Next;
}
if (now==NULL || now-PID=0)/*未查找到后备进程*/
return FALSE;/**/
free(now);
last-Next = NULL;
BatchQueue = BatchQueue-Next;
free(bt);
return TRUE;
}
int UnSuspendProc(int id)
{
PCB *now = ProcQueue;
if (ProcQueue==NULL) return FALSE;
while (now != NULL)
{
if (now-PID == id)
{
now-Sts = READY;
return TRUE;
}
}
return FALSE;
}
int UpdateBatchs()
{
Batch *bt = BatchQueue;
PCB *last = ProcQueue, *now;
while (bt != NULL)
{
bt-pcb = NULL;
bt = bt-Next;
}
if (ProcQueue == NULL) return TRUE;
while (last-Sts==RUN last-PID=0 last-Time=0)
{
ProcQueue = ProcQueue-Next;
free(last);
last = ProcQueue;
}
now = last-Next;
while (now != NULL)
{
if (now-Sts==RUN now-PID=0 now-Time=0)/*如果该进程是运行中的一般进程并已执行完毕*/
{
last-Next = now-Next;
free(now);
}
else
last = last-Next;
now = last-Next;
}
bt = BatchQueue;
now = ProcQueue;
while (bt != NULL now != NULL)
{
bt-pcb = now;
now-Sts = RUN;
bt = bt-Next;
now = now-Next;
}
while (now != NULL)
{
if (now-Sts == RUN)
{
now-Sts = SUSPEND;
}
now = now-Next;
}
return TRUE;
}
int PassSeconds(int n)
{
static int time = 0;
int i=0, ProcEnd = FALSE;
PCB *pcb = ProcQueue;
Batch *bt = BatchQueue;
if (bt == NULL) return FALSE;
time += n;
if (time=TIME)
{
i = time/TIME;/*经过多少时间段*/
time = time%TIME;
}
while (bt != NULL)/*更新进程运行时间*/
{
if (bt-pcb-PID=0)
{
bt-pcb-Time -= n;
if (bt-pcb-Time = 0)/*进程结束*/
{
ProcEnd = TRUE;
}
}
bt = bt-Next;
}
if (i 0)
{
while (pcb != NULL)/*更新进程优先权（动态优先权）*/
{
if (pcb-Sts == RUN pcb-PID=0)/*运行的进程优先权降低*/
{
pcb-Prior -= i;
if (pcb-Prior 0)
pcb-Prior = 0;
}
else if (pcb-Sts == SUSPEND pcb-PID=0)/*挂起的进程优先权升高*/
pcb-Prior += i;
pcb = pcb-Next;
}
}
if (i0)
SortProcQueue();/*如果优先级有变动则重新排序*/
if (ProcEnd || i0)
{
UpdateBatchs();/*更新多道进程*/
}
return TRUE;
}
/****************************************************************/
/*图形界面相关函数*/
/****************************************************************/
/*表格的单位宽度和高度*/
#define WIDTH 64
#define HEIGHT 12
void *black=NULL;/*背景色方格，使用它擦出表格中的图形*/
int InitGraph()/*初始化图形界面*/
{
int GraphDriver; /* The Graphics device driver */
int GraphMode; /* The Graphics mode value */
int ErrorCode;
GraphDriver = DETECT; /* Request auto-detection */
initgraph( GraphDriver, GraphMode, "" );
ErrorCode = graphresult(); /* Read result of initialization*/
if( ErrorCode != grOk )
{ /* Error occured during init */
printf(" Graphics System Error: %s\n", grapherrormsg( ErrorCode ) );
getch();
return FALSE;
}
cleardevice();
black = (void*)malloc(imagesize(1,1,WIDTH-1,HEIGHT-1));
getimage(1,1,WIDTH-1,HEIGHT-1,black);
DrawFrame();
DrawData();
return TRUE;
}
int DrawFrame()/*画边框和表头*/
{
settextjustify(CENTER_TEXT, CENTER_TEXT);
gprintf(320, HEIGHT/2-1, "Multi-Batch System Emulation");
settextjustify(LEFT_TEXT, TOP_TEXT);
moveto(0,HEIGHT);
lineto(0,479);
lineto(639,479);
lineto(639,HEIGHT);
lineto(0,HEIGHT);
line(WIDTH*4,HEIGHT,WIDTH*4,479);
line(WIDTH*7,HEIGHT,WIDTH*7,479);
line(0,HEIGHT*2,639,HEIGHT*2);
line(0,HEIGHT*3,639,HEIGHT*3);
gprintf(HEIGHT*0+2,HEIGHT*1+2,"System Batchs");/*系统多道列表头*/
gprintf(HEIGHT*0+2,HEIGHT*2+2,"Batch");
gprintf(WIDTH*1+2,HEIGHT*2+2,"ProcID");
gprintf(WIDTH*2+2,HEIGHT*2+2,"Time");
gprintf(WIDTH*3+2,HEIGHT*2+2,"Prior");
gprintf(WIDTH*4+2,HEIGHT*1+2,"Suspended Processes");/*挂起队列列表头*/
gprintf(WIDTH*4+2,HEIGHT*2+2,"ProcID");
gprintf(WIDTH*5+2,HEIGHT*2+2,"Time");
gprintf(WIDTH*6+2,HEIGHT*2+2,"Prior");
gprintf(WIDTH*7+2,HEIGHT*1+2,"Ready Processes");/*就绪队列列表头*/
gprintf(WIDTH*7+2,HEIGHT*2+2,"ProcID");
gprintf(WIDTH*8+2,HEIGHT*2+2,"Time");
gprintf(WIDTH*9+2,HEIGHT*2+2,"Prior");
}
int DrawData()/*绘制系统数据*/
{
int numRun=0, numSus=0, numRed=0;/*运行挂起和就绪的进程各有多少*/
PCB* now = ProcQueue;
int x=0, y=0;
while (now != NULL)
{
switch(now-Sts)
{
case RUN:
x = WIDTH*1;
y = HEIGHT*(3+(numRun++));
break;
case SUSPEND:
x = WIDTH*4;
y = HEIGHT*(3+(numSus++));
break;
case READY:
x = WIDTH*7;
y = HEIGHT*(3+(numRed++));
break;
}
if (now-Sts==RUN)/*该进程为正在运行的进程*/
{
putimage(x-WIDTH+1,y+1,black,COPY_PUT);
gprintf(x-WIDTH+2,y+2,"%d",numRun);
}
if (now-PID=0)/*该进程不是后备进程*/
{
putimage(x+1,y+1,black,COPY_PUT);
gprintf(x+2,y+2,"%d",now-PID);
putimage(x+1+WIDTH,y+1,black,COPY_PUT);
gprintf(x+WIDTH+2,y+2,"%d",now-Time);
putimage(x+1+WIDTH*2,y+1,black,COPY_PUT);
gprintf(x+WIDTH*2+2,y+2,"%d",now-Prior);
}
else
{
putimage(x+1,y+1,black,COPY_PUT);
putimage(x+1+WIDTH,y+1,black,COPY_PUT);
putimage(x+1+WIDTH*2,y+1,black,COPY_PUT);
gprintf(x+2,y+2,"system idle process");
}
now = now-Next;
}
}
int DlgGetNum(char *buf,int l,int t,int r,int b,int gettime)
{
char ch;
int pos=0;
bar(l,t,r,b);
gprintf(l+10,t+5,"Add new Process");
if (gettime)
gprintf(l+10,t+20,"input the time:");
else
gprintf(l+10,t+20,"input the priority:");
while (1)
{
ch = getch();
if (ch == ENTER)/*如果输入了回车键*/
{
if(pos!=0)/*如果位置不在第一位(回车键不准第一个输入)*/
{
buf[pos]='\0';
break;
}
}
else if (ch='0' ch='9')
{
buf[pos++]=ch;
buf[pos]='\0';
}
else if (ch == ESC)
{
return FALSE;
}
else/*其他按键均按BackSpace处理*/
{
--pos;
buf[pos]='\0';
}
if (pos0)
{ pos=0; buf[pos]='\0';}
else if (pos4)/*最多输入4位数*/
{ pos=4; buf[pos]='\0';}
bar(l,t+35,r,t+47);
gprintf(l+50,t+35,buf);
}
return TRUE;
}
int NewProcDlg()
{
int l=200,t=150,r=380,b=200,pos=0,prior=0,time=0;
char buf[5],ch;
PCB *pcb;
void* bg = (void*)malloc(imagesize(l,t,r,b));
getimage(l,t,r,b,bg);
setfillstyle(1,2);
flushall();
/*******输入优先级**********/
if (!DlgGetNum(buf,l,t,r,b,FALSE))
goto exit;
prior = atoi(buf);
/*******输入时间**********/
pos=0;
buf[pos]='\0';
if (!DlgGetNum(buf,l,t,r,b,TRUE))
goto exit;
time = atoi(buf);
InsertProc(prior, time);
exit:
putimage(l,t,bg,COPY_PUT);
free(bg);
return TRUE;
}
int gprintf( int xloc, int yloc, char *fmt, ... )/*图形系统中的格式输出*/
{
va_list argptr; /* Argument list pointer */
char str[140]; /* Buffer to build sting into */
int cnt; /* Result of SPRINTF for return */
va_start( argptr, format ); /* Initialize va_ functions */
cnt = vsprintf( str, fmt, argptr ); /* prints string to buffer */
outtextxy( xloc, yloc, str ); /* Send string in graphics mode */
va_end( argptr ); /* Close va_ functions */
return( cnt ); /* Return the conversion count */
}
/****************************************************************/
/*main函数*/
int main()
{
clock_t start=0, end=0;
char kb;
InitBatchs(3);/*初始化为3道系统*/
InitGraph();
while (1)
{
start = end = clock();
while (!kbhit())
{
start = clock();
if ((start-end)/18.2 = 1)/*时间过了一秒*/
{
start = end = clock();
PassSeconds(1);
cleardevice();
DrawFrame();
DrawData();
}
}
kb = getch();
switch (kb)
{
case ESC:
closegraph();
return 0;
case 'w':
AddBatch();
UpdateBatchs();
cleardevice();
DrawFrame();
DrawData();
break;
case 's':
DeleteBatch();
UpdateBatchs();
cleardevice();
DrawFrame();
DrawData();
break;
case 'i':
NewProcDlg();
UpdateBatchs();
DrawFrame();
DrawData();
break;
}
}
return 0;
}
你先用C++写，然后做成DLL。
再用java去调就好了。
一般java做底层控制和调用都会这么做。
就像io什么的，都是去调用C的代码完成的
一般java调用c写的dll代码都比较方便。
c调用java的代码几乎不可能。
public class CLSS_ch2 {
public static void main(String[] args) {
int sum = 0;
for (int i = 1; i = 100; i++) {
if (i % 10 == 3)
continue;
sum += i;
}
System.out.println(sum);
}
}
计算机图形技术组的成员在1993年开发出了 Lua。它被设计成为脚本语言，是一种不可获取的过程式编程语言，以简单而强大而闻名。
import java.util.ArrayList;
import java.util.List;
public class Question {
// 调度总站
class DiaoDuZhan{
private ListClient list;
public Client getClient(){ // 获得客户
if(list != null list.size() 0){
Client client = list.get(0);
list.remove(client);
return client;
}else{
return null;
}
}
public void addClient(Client client){
if(list == null){
list = new ArrayListClient();
}
list.add(client);
}
}
// 客户
interface Client{
public void setService(Service service);
public Service getSerive();
}
// 服务
interface Service{
public void doService();
}
// 服务员
class waiter{
DiaoDuZhan diaoduzhan;
public DiaoDuZhan getDiaoduzhan() {
return diaoduzhan;
}
public void setDiaoduzhan(DiaoDuZhan diaoduzhan) {
this.diaoduzhan = diaoduzhan;
}
public void doNext(){
Client client = diaoduzhan.getClient();
if(client != null)
client.getSerive().doService();
}
}
}
public class PrivilegeProcess {
public static void main(String[] args) {
MyQueue myqueue = new MyQueue();//声明队列
PCB[] pcb = {new PCB(001,8,1),new PCB(002,7,9),new PCB(003,3,8),new PCB(004,1,7),new PCB(005,7,4)};
PCB para = new PCB();
for(int i=0;ipcb.length;i++){//初始化后首先执行一次排序，这里使用的是选择排序，优先级高的先入队
for(int j=i;jpcb.length;j++){
if(pcb[i].privilege pcb[j].privilege){
para = pcb[i];
pcb[i] = pcb[j];
pcb[j] = para;
}
}
}
System.out.println("初次入队后各进程的顺序：");
for(int i=0;ipcb.length;i++){
System.out.println("初次入队后 # processname : " + pcb[i].name + " totaltime : " + pcb[i].totaltime + " privilege :" + pcb[i].privilege);
}
System.out.println();
myqueue.start(pcb);
}
}
class MyQueue {
int index = 0;
PCB[] pc = new PCB[5];
PCB[] pc1 = new PCB[4];
PCB temp = new PCB();
public void enQueue(PCB process){//入队算法
if(index==5){
System.out.println("out of bounds !");
return;
}
pc[index] = process;
index++;
}
public PCB deQueue(){//出队算法
if(index==0)
return null;
for(int i=0;ipc1.length;i++){
pc1[i] = pc[i+1];
}
index--;
temp = pc[0];
for(int i=0;ipc1.length;i++){
pc[i] = pc1[i];
}
return temp;
}
public void start(PCB[] pc){//显示进程表算法
while(pc[0].isNotFinish==true||pc[1].isNotFinish==true||pc[2].isNotFinish==true||pc[3].isNotFinish==true||pc[4].isNotFinish==true){
//*注意：||运算符，所有表达式都为false结果才为false,否则为true
for(int i=0;ipc.length;i++){
pc[i].run(this);
}
System.out.println();
for(int i=0;ipc.length;i++){//所有进程每执行完一次时间片长度的运行就重新按优先级排列一次
for(int j=i;jpc.length;j++){
if(pc[i].privilege pc[j].privilege){
temp = pc[i];
pc[i] = pc[j];
pc[j] = temp;
}
}
}
}
}
}
class PCB {//声明进程类
int name,totaltime,runtime,privilege;
boolean isNotFinish;
public PCB(){
}
public PCB(int name, int totaltime, int privilege){
this.name = name;//进程名
this.totaltime = totaltime;//总时间
this.privilege = privilege;//优先级别
this.runtime = 2;//时间片，这里设值为2
this.isNotFinish = true;//是否执行完毕
System.out.println("初始值： processname : " + name + " totaltime : " + totaltime + " privilege :" + privilege );
System.out.println();
}
public void run (MyQueue mq){//进程的基于时间片的执行算法
if(totaltime1){
totaltime-=runtime;//在总时间大于1的时候，总时间=总时间-时间片
privilege--;
System.out.println(" processname : " + name + " remaintime : " + totaltime + " privilege :" + privilege );
}else if(totaltime==1){
totaltime--;//在总时间为1时，执行时间为1
privilege--;
System.out.println(" processname : " + name + " remaintime : " + totaltime + " privilege :" + privilege );
}else{
isNotFinish = false;//总时间为0，将isNotFinish标记置为false
}
if(isNotFinish==true){
mq.deQueue();
mq.enQueue(this);
}
}
}
