操作系统实验二

# 操作系统实验二

# 前情提要 Again:

实验介绍很多，很多，非常多，让人看的很头大，越看越感觉这实验是要你把系统进程管理手搓出来，然后一种感觉油然而生。

老师太看得起我们啦！！！

后来仔细看了一下$shell$ 命令行的内容，发现，好像，似乎，大概，不需要我们真的创建进程然后去管理，我们只需要去模拟这个进程管理的流程就行了，然后就有了这样的简易版的进程模拟程序：

# 一、进程结构体和资源结构体

进程结构体：

struct ProcessNode
{
	int pid;
	string name;
	vector <int> reslist;
	int state; // state 0->Ready 1->Block 2->Running 3->release 
	int priority; //优先级 
	int tim; // 建立时间 
	ProcessNode* fa;
	ProcessNode* child; 
	bool operator < (const ProcessNode & ot) const
	{
		if(priority!=ot.priority)
			return priority>ot.priority;
		return tim<ot.tim;
	}
};

资源结构体：

struct ProcessNode
{
	int pid;
	string name;
	vector <int> reslist;
	int state; // state 0->Ready 1->Block 2->Running 3->release 
	int priority; //优先级 
	int tim; // 建立时间 
	ProcessNode* fa;
	ProcessNode* child; 
	bool operator < (const ProcessNode & ot) const //排序方法，先根据优先级排序，再根据时间顺序排序
	{
		if(priority!=ot.priority)
			return priority>ot.priority;
		return tim<ot.tim;
	}
};

# 二、进程队列、阻塞队列、资源管理模块

vector <ProcessNode > ready;
vector <ProcessNode > block;
vector <ResNode> res;

# 三、进程创建

void create(string name,int prio)
{
	ProcessNode newnode;
	newnode.child=NULL,newnode.fa=NULL;
	newnode.pid=++pidcnt;
	newnode.priority=prio;
	newnode.tim=++timcnt;
	newnode.name=name;
	ready.push_back(newnode);
	sort(ready.begin(),ready.end());
	return;
}

# 四、资源请求

void request(char name)
{
	int len=res.size();
	for(int i=0;i<len;i++)
	{
		if(res[i].name==name && res[i].available==true)
		{
			res[i].available=false;
			ready[0].reslist.push_back(res[i].rid);
			cout<<"Process "<<ready[0].name<<" is running"<<endl;
		}
		else if(res[i].name==name && res[i].available==false)
		{
			ProcessNode t=ready[0];
			ready[0].reslist.push_back(res[i].rid);
			ready.erase(ready.begin());
			block.push_back(t);
			cout<<"Process "<<t.name<<" is blocked;Process "<<ready[0].name<<" is running"<<endl;
		}
	}
	return;
}

# 五、进程释放

bool check()
{
	if(block.size()==0)
		return false;
	int len=block[0].reslist.size();
	for(int i=0;i<len;i++)
	{
		int l1=res.size();
		for(int j=0;j<l1;j++)
		{
			if(res[j].rid==block[0].reslist[i])
			{
				if(res[j].available==false)
					return false;
				break; 
			}
		}
	}
	return true;
}
void release()
{
	int l1=ready[0].reslist.size();
	for(int i=0;i<l1;i++)
	{
		int l2=res.size();
		for(int j=0;j<l2;j++)
		{
			if(res[j].rid==ready[0].reslist[i])
				res[j].available=true;
		}
	}
	ready.erase(ready.begin());
	while(check())
	{
		ProcessNode t=block[0];
		cout<<"Process "<<t.name<<" is activate"<<endl;
		block.erase(block.begin());
		ready.push_back(t);
	}
	sort(ready.begin(),ready.end());
	if(ready.size()!=0)
		cout<<"Process "<<ready[0].name<<" is running"<<endl;
	else
		cout<<"All the Processes have finished"<<endl;
	return;
}

# 六、完整程序：

#include <bits/stdc++.h>
using namespace std;
int pidcnt,ridcnt,timcnt;
struct ResNode
{
	char name;
	int rid;
	bool available;
	ResNode(char nn,int rr,bool aa)
	{
		name=nn,rid=rr,available=aa;
	}
	ResNode()
	{
	}
};
struct ProcessNode
{
	int pid;
	string name;
	vector <int> reslist;
	int state; // state 0->Ready 1->Block 2->Running 3->release
    // state其实可以不加，但是为了完整性可以加一下
	int priority; //优先级 
	int tim; // 建立时间 
	ProcessNode* fa;
	ProcessNode* child; 
	bool operator < (const ProcessNode & ot) const
	{
		if(priority!=ot.priority)
			return priority>ot.priority;
		return tim<ot.tim;
	}
};
vector <ProcessNode > ready;
vector <ProcessNode > block;
vector <ResNode> res;
void create(string name,int prio)
{
	ProcessNode newnode;
	newnode.child=NULL,newnode.fa=NULL;
	newnode.pid=++pidcnt;
	newnode.priority=prio;
	newnode.tim=++timcnt;
	newnode.name=name;
	ready.push_back(newnode);
	sort(ready.begin(),ready.end());
	return;
}
void init_res()
{
	//一共十种资源，每种资源初始都可以使用,每种资源的命名方式是由A,B,C,...以此类推 
	for(int i=0;i<10;i++)
		res.push_back(ResNode(i+'A',++ridcnt,true));
	return;
}
void request(char name)
{
	int len=res.size();
	for(int i=0;i<len;i++)
	{
		if(res[i].name==name && res[i].available==true)
		{
			res[i].available=false;
			ready[0].reslist.push_back(res[i].rid);
			cout<<"Process "<<ready[0].name<<" is running"<<endl;
		}
		else if(res[i].name==name && res[i].available==false)
		{
			ProcessNode t=ready[0];
			ready[0].reslist.push_back(res[i].rid);
			ready.erase(ready.begin());
			block.push_back(t);
			cout<<"Process "<<t.name<<" is blocked;Process "<<ready[0].name<<" is running"<<endl;
		}
	}
	return;
}
bool check()
{
	if(block.size()==0)
		return false;
	int len=block[0].reslist.size();
	for(int i=0;i<len;i++)
	{
		int l1=res.size();
		for(int j=0;j<l1;j++)
		{
			if(res[j].rid==block[0].reslist[i])
			{
				if(res[j].available==false)
					return false;
				break; 
			}
		}
	}
	return true;
}
void release()
{
	int l1=ready[0].reslist.size();
	for(int i=0;i<l1;i++)
	{
		int l2=res.size();
		for(int j=0;j<l2;j++)
		{
			if(res[j].rid==ready[0].reslist[i])
				res[j].available=true;
		}
	}
	ready.erase(ready.begin());
	while(check())
	{
		ProcessNode t=block[0];
		cout<<"Process "<<t.name<<" is activate"<<endl;
		block.erase(block.begin());
		ready.push_back(t);
	}
	sort(ready.begin(),ready.end());
	if(ready.size()!=0)
		cout<<"Process "<<ready[0].name<<" is running"<<endl;
	else
		cout<<"All the Processes have finished"<<endl;
	return;
}
int main()
{
	init_res();
	cout<<"请输入命令"<<endl;
	string op;
	int prio;
	while(cin>>op)
	{
		if(op=="cr")
		{
			string name;
			cin>>name>>prio;
			create(name,prio);
			cout<<"Process "<<ready[0].name<<" is running"<<endl;
		}
		else if(op=="rq")
		{
			char name;
			cin>>name;
			request(name);
		}
		else if(op=="rel")
			release();
		else if(op=="esc")
			break;
	}
	return 0;
}

可能有些不完善的地方，如有问题，请评论区指出。