银行家算法模拟资源分配代码,C代码库,德仔网

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【C】银行家算法模拟资源分配
作者:空云万里晴 / 发布于2012/11/19/ 855
#include "stdafx.h"
#include <iostream>
using namespace std;

bool checkSafe(int *Need,int *Allocation,int *Available,int p,int r);

int _tmain(int argc, _TCHAR* argv[])
{
	// 进程数为5，资源数为3
	int p=5,r=3;							
	// Max为5*3的最大需求矩阵，Available为可利用资源向量，
	// Allocation为5*3的分配矩阵，Need为5*3的需求矩阵,请求向量Request1
	int *Max,*Available,*Allocation,*Need,*Request1;	

	Max = new int[p*r];
	Available = new int[r];
	Allocation = new int[p*r];
	Need = new int[p*r];
	Request1 = new int[r];

	// 初始化Max矩阵
	// 7  5  3
	// 3  2  2
	// 9  0  2
	// 2  2  2 
	// 4  3  3 
	*(Max+0*r+0) = 7;
	*(Max+0*r+1) = 5;
	*(Max+0*r+2) = 3;
	*(Max+1*r+0) = 3;
	*(Max+1*r+1) = 2;
	*(Max+1*r+2) = 2;
	*(Max+2*r+0) = 9;
	*(Max+2*r+1) = 0;
	*(Max+2*r+2) = 2;
	*(Max+3*r+0) = 2;
	*(Max+3*r+1) = 2;
	*(Max+3*r+2) = 2;
	*(Max+4*r+0) = 4;
	*(Max+4*r+1) = 3;
	*(Max+4*r+2) = 3;

	// 初始化Allocation矩阵
	// 0  1  0
	// 2  0  0
	// 3  0  2
	// 2  1  1 
	// 0  0  2 
	*(Allocation+0*r+0) = 0;
	*(Allocation+0*r+1) = 1;
	*(Allocation+0*r+2) = 0;
	*(Allocation+1*r+0) = 2;
	*(Allocation+1*r+1) = 0;
	*(Allocation+1*r+2) = 0;
	*(Allocation+2*r+0) = 3;
	*(Allocation+2*r+1) = 0;
	*(Allocation+2*r+2) = 2;
	*(Allocation+3*r+0) = 2;
	*(Allocation+3*r+1) = 1;
	*(Allocation+3*r+2) = 1;
	*(Allocation+4*r+0) = 0;
	*(Allocation+4*r+1) = 0;
	*(Allocation+4*r+2) = 2;
	
	// 初始化可利用资源向量Available
	// 3  3  2
	*(Available+0) = 3;
	*(Available+1) = 3;
	*(Available+2) = 2;


	// 初始化Need矩阵
	for(int i=0;i<p*r;i++)
		*(Need+i) = *(Max+i) - *(Allocation+i);

	// p1请求资源Request1（1,0,2）
	*(Request1+0) = 1;
	*(Request1+1) = 0;
	*(Request1+2) = 2;

	int flag = 0;
	for(int i=0;i<r;i++)
	{
		if(*(Request1+i)>*(Need+1*r+i))
		{
			flag = 0;
			break;
		}
		else
		{
			flag = 1;
		}
	}
	if(flag==1)
	{
		int flag2 = 0;
		for(int i=0;i<r;i++)
		{
			if(*(Request1+i)>*(Available+i))
			{
				flag = 0;
				break;
			}
			else
			{
				flag2 = 1;
			}
		}
		if(flag2==1)	
		{	
			// 系统试探着进行资源分配
			for(int i=0;i<r;i++)
			{
				*(Available+i) -= *(Request1+i);
				*(Allocation+1*r+i) += *(Request1+i);
				*(Need+1*r+i) -= *(Request1+i);
			}
			if(checkSafe(Need,Allocation,Available,p,r))
			{
				cout<<"分配资源后系统处于安全状态，可进行分配！"<<endl;
			}
			else
			{
				cout<<"分配资源后系统处于不安全状态，系统不分配该资源！"<<endl;
				// 本次试探分配作废，恢复原来资源分配状态
				for(int i=0;i<r;i++)
				{
					*(Available+i) += *(Request1+i);
					*(Allocation+1*r+i) -= *(Request1+i);
					*(Need+1*r+i) += *(Request1+i);
				}
			}

		}
		else
		{
			cout<<"请求资源出错，无足够资源可分配！"<<endl;
		}
	}
	else
	{
		cout<<"请求资源出错，请求资源数不能大于需求资源数！"<<endl;
	}

	delete[] Max;
	delete[] Available;
	delete[] Allocation;
	delete[] Need;
	delete[] Request1;

	return 0;
}


bool checkSafe(int *Need,int *Allocation,int *Available,int p,int r)
{

	int i=0,j=0,k=0,m=0,count=0 ,flag1=0,flag2=0;
	int *list,*Work;	// 工作向量Work，安全序列list
	bool *Finish;		// 完成标志Finish
	Work = new int[r];
	Finish = new bool[p];
	list = new int[p];

	// 初始化完成标志Finish，默认为false
	for(i=0;i<p;i++)
		*(Finish+i) = false;

	// 初始化工作向量Work
	for(i=0;i<r;i++)
		*(Work+i) = *(Available+i);

	// 进行安全检查
	while(k<p)
	{
		flag1 = 0;
		for(j=0;j<r;j++)
		{
			if(*(Finish+m)!=true)
			{
				if(*(Need+m*r+j)>*(Work+j))
				{
					flag1 = 0;
					break;
				}
				flag1 = 1;
			}

		}
		if(flag1==1)
		{
			for(j=0;j<r;j++)
			{
				*(Work+j) += *(Allocation+m*r+j);
			}
			*(Finish+m) = true;
			*(list+k) = m;
			count = 0;
			k++;
		}
		else
		{
			count++;
		}
		if(count==5)
			break;
		m++;
		if(m==5)
			m=0;
	}
	
	// 若所有进程的*(Finish+i)==true,表示系统处于安全状态
	for(i=0;i<p;i++)
	{
		if(*(Finish+i)!=true)
		{
			flag2 = 0;
			break;
		}
		else
		{
			flag2 =1;
		}
	}

	delete[] Work;
	delete[] Finish;
	
	if(flag2==1)
	{	
		cout<<"存在安全序列：";
		for(i=0;i<p;i++)
			cout<<" "<<*(list+i);
		cout<<endl;
		delete[] list;
		return true;
	}
	else
	{
		return false;
	}

}
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