实验一 进程

2011210549 崔晶

1.本实验实现的功能有：创建一个进程，撤销一个进程，挂起一个进程

2.本实验初始化的进程块状态如图所示：(自定义)

3.程序如下：

# include<stdio.h>

# include<string.h>

//进程块的数据结构

struct PCB_Struct{

char pb[6];

char status;//进程块所处的状态，p表示正在运行，r表示就绪，w表示等待 int next;

int prior;

}pcb[255];

int srun = 2;//运行队列头指针

int erun;//运行队列尾指针

int sready = 3;//就绪队列头指针

int eready;//就绪队列尾指针

int swait = 0;//等待队列头指针

int ewait;//等待队列尾指针

//初始化静态链表,运行队列2，7，9；等待队列0，1，4，6；就绪队列3，5，10，17； void init(){

strcpy(pcb[0].pb,"PCB0");

pcb[0].next=1;

pcb[0].status='p';

pcb[0].prior=-1;

strcpy(pcb[1].pb,"PCB1");

pcb[1].next=4;

pcb[1].status='w';

pcb[1].prior=0;

strcpy(pcb[2].pb,"PCB2");

pcb[2].next=7;

pcb[2].status='r';

pcb[2].prior=-1;

strcpy(pcb[3].pb,"PCB3");

pcb[3].next=5;

pcb[3].status='r';

pcb[3].prior=-1;

strcpy(pcb[4].pb,"PCB4");

pcb[4].next=6;

pcb[4].status='w';

pcb[4].prior=1;

strcpy(pcb[5].pb,"PCB5");

pcb[5].next=10;

pcb[5].status='r';

pcb[5].prior=3;

strcpy(pcb[6].pb,"PCB6");

pcb[6].next=-1;

pcb[6].status='w';

pcb[6].prior=4;

ewait = 6;

strcpy(pcb[7].pb,"PCB7");

pcb[7].next=9;

pcb[7].status='p';

pcb[7].prior=2;

strcpy(pcb[9].pb,"PCB9");

pcb[9].next=-1;

pcb[9].status='p';

pcb[9].prior=7;

erun = 9;

strcpy(pcb[10].pb,"PCB10");

pcb[10].next=17;

pcb[10].status='r';

pcb[10].prior=5;

strcpy(pcb[17].pb,"PCB17");

pcb[17].next=-1;

pcb[17].status='r';

pcb[17].prior=10;

eready = 17;

}

//插入就绪队列

void insert1(char* name){

for(int j = 0; j < 255; j++){

if(strcmp(pcb[j].pb,"-1") == 0){

strcpy(pcb[j].pb,name);

pcb[j].next = -1;

pcb[j].prior = eready;

pcb[eready].next = j;

eready = j;

return;

}

}

}

//插入等待队列

void insert2(char* name){

for(int j = 0; j < 255; j++){

if(strcmp(pcb[j].pb,"-1") == 0){

strcpy(pcb[j].pb,name);

pcb[j].next = -1;

pcb[j].prior = ewait;

pcb[ewait].next = j;

ewait = j;

return;

}

}

}

//创建一个进程并插入就绪队列

void creatpcb(char* name){

for(int i = 0; i < 255; i++){

if(strcmp(pcb[i].pb,name) == 0){

printf("要创建的进程已存在！");

return;

}

}

insert1(name);

}

//输出目前正在运行或等待或就绪的队列

void Print(char ch){

int p ;//当前进程块的序号

//输出等待队列

if(ch == 'w'){

p = swait;

while(pcb[p].next != -1){

printf("PCB%d ",p);

p = pcb[p].next;

}

printf("%s\n",pcb[ewait].pb);

}

//输出就绪队列

else if(ch == 'r'){

p = sready;

while(pcb[p].next != -1){

printf("PCB%d ",p);

p = pcb[p].next;

}

printf("%s\n",pcb[eready].pb);

}

//输出运行队列

else{

p = srun;

while(pcb[p].next != -1){

printf("PCB%d ",p);

p = pcb[p].next;

}

printf("%s\n",pcb[erun].pb);

}

}

void Givestatus(int s,int i){

strcpy(pcb[i].pb,"-1");

pcb[s].prior = -1;

pcb[i].next = -1;

pcb[i].prior = -1;

pcb[i].status = 'N';

}

//撤销一个进程

void Deletepcb(char* name){

if(strcmp("-1",name) != 0)

for(int i = 0; i < 255; i++){

if(strcmp(pcb[i].pb,name) == 0){

if(i == srun ){

srun = pcb[i].next;

Givestatus(srun,i);

return ;

}

if(i == erun ){

erun = pcb[i].prior;

pcb[erun].next = -1;

Givestatus(srun,i);

return ;

}

if(i == sready ){

sready = pcb[i].next;

pcb[sready].prior = -1;

Givestatus(erun,i);

return;

}

if(i == eready ){

eready = pcb[i].prior;

pcb[eready].next = -1;

Givestatus(eready,i);

return;

}

if(i == swait ){

swait = pcb[i].next;

pcb[swait].prior = -1;

Givestatus(swait,i);

return;

}

if(i == ewait ){

ewait = pcb[i].prior;

pcb[ewait].next = -1;

Givestatus(ewait,i);

return;

}

pcb[pcb[i].next].prior =pcb[i].prior;

pcb[pcb[i].prior].next =pcb[i].next;

pcb[i].next = -1;

pcb[i].prior = -1;

pcb[i].status = 'N';

return;

}

}

}

//挂起一个进程并插入等待队列

void Letwait(char* name){

for(int i = 0; i < 255; i++){

if(strcmp(pcb[i].pb,name) == 0 && pcb[i].status == 'p' ){ Deletepcb(name);//从运行队列中删除的进程 insert2(name);//插入等待队列

return;

}

}

printf("您要挂起的进程不存在!");

}

void main(){

int choice;//选项

int tag = 1;

for(int i = 0; i < 255; i++){

strcpy(pcb[i].pb,"-1");

pcb[i].next = -1;

pcb[i].prior = -1;

pcb[i].status = 'N';

}

init();

printf("目前就绪的进程有:");

Print('r');

printf("目前等待的进程有:");

Print('w');

printf("目前运行的进程有:");

Print('p');

while(choice != 4){

printf("choice:\n");

printf("1:创建一个进程\n");

printf("2:撤销一个进程\n");

printf("3:挂起一个进程\n");

printf("4:退出\n");

printf("enter your choice!\n");

char name[6];

scanf("%d",&choice);

if(choice != 1 && choice != 2 && choice != 3 && choice != 4) printf("\ndon't have this choice!Enter your choice again!");

if(choice == 1){

printf("输入要创建的进程名:\n");

scanf("%s",name);

creatpcb(name);

printf("目前就绪的进程有:");

Print('r');

printf("目前等待的进程有:");

Print('w');

printf("目前运行的进程有:");

Print('p');

}

else if(choice == 2){

printf("输入要撤销的进程名:\n");

scanf("%s",name);

Deletepcb(name);

printf("目前就绪的进程有:");

Print('r');

printf("目前等待的进程有:");

Print('w');

printf("目前运行的进程有:");

Print('p');

}

else if(choice == 3){

printf("输入要挂起的进程名:\n");

scanf("%s",name);

Letwait(name);

printf("目前就绪的进程有:");

Print('r');

} } printf("目前等待的进程有:"); Print('w'); printf("目前运行的进程有:"); Print('p'); } printf("\----------------------------------------------------\n");

4.结果截屏如图所示：

5.实验分析：程序中仍含有大量冗余代码，可进一步改进。