128.cpp

此源代码是操作系统中进程资源分配著名的银行家算法

#include<stdafx.h>
#include<iostream.h>
#include<stdlib.h>
#include<windows.h>

#define RES_TYPES 4
#define PROCESS_NUM 6

int available[RES_TYPES]={4,4,4,4};
int max_requ[PROCESS_NUM ][RES_TYPES ] ={{1,2,3,2},{2,1,2,1},{1,1,1,1},{2,1,1,1},{1,2,1,0},{1,0,1,1}};
int requ_seq[PROCESS_NUM][100]={{8,1,2,2,3,3,3,4,4},{6,1,2,3,4,1,3},{4,3,4,1,2},{5,4,3,2,1,1},{4,2,2,3,1},{3,1,4,3}};

int requ_resource(int res_idx,int num);
void release_resource(int res_idx,int num);

int process_point[PROCESS_NUM]={1,1,1,1,1,1};
int process_completed[PROCESS_NUM]={1,1,1,1,1,1};
int resource_alloc[PROCESS_NUM][RES_TYPES]={{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0},{0,0,0,0}};
int resource_need[PROCESS_NUM][RES_TYPES]={{1,2,3,2},{2,1,2,1},{1,1,1,1},{2,1,1,1},{1,2,1,0},{1,0,1,1}};

int *k;
int a[RES_TYPES];

int exist_uncompleted_process()
{
    Sleep(rand()%1000);
	int i,j;
	j=0;
	for(i=0;i<6;i++)
	{
		if(*(process_completed+i)==0)
			j++;
	}
	if(j==6)  return 0;
	else      return 1;
}

int get_uncompleted_process_id()
{
	int p;
    //Sleep(rand()%10);
	p=rand()%6;
  
	while(*(process_completed+p)!=1)
	{
		p=rand()%6;
	}
    if(*(process_completed+p)==1)
    return p;
}

int pre_alloc(int i,int j)
{
	int m,b,p;
	p=0;
	for(b=*k;b<=requ_seq[i][0];b++)
	{
		m=requ_seq[i][b];
		if(*(available+m-1)>0)
		{
			*(available+m-1)=*(available+m-1)-1;
			p++;
		}
		else return 0;
	}
	if(p==(requ_seq[i][0]-*k+1))
		return 1;
}

void alloc(int i,int j)
{
	int d;
	for(d=0;d<4;d++)
	{
		*(available+d)=*(a+d);
	}
    *(available+j-1)=*(available+j-1)-1;
}

void release_resource(int res_idx,int num)
{
	*(available+res_idx-1)=*(available+res_idx-1)+1;
}

int main()
{
	int i,j,w;
	int n,s,r,t;
	int c[6][4];
	while(exist_uncompleted_process())
	{
		Sleep(rand()%500);
		i=get_uncompleted_process_id();
		k=&process_point[i];
		j=requ_seq[i][*k];
		for(w=0;w<4;w++)
		{
			*(a+w)=*(available+w);
		}
		if(pre_alloc(i,j))
		{
			alloc(i,j);
			*(*(resource_alloc+i)+j-1)=*(*(resource_alloc+i)+j-1)+1;
			for(n=0;n<6;n++)
			{
				c[i][n]=max_requ[i][n]-resource_alloc[i][n];
			}
			
			cout<<"进程"<<i+1;
		    cout<<"得到资源数"<<resource_alloc[i][0]<<" ";
			cout<<resource_alloc[i][1]<<" ";
			cout<<resource_alloc[i][2]<<" ";
			cout<<resource_alloc[i][3]<<" "<<endl;
			cout<<"进程"<<i+1<<"尚需资源数"<<c[i][0]<<" ";
			cout<<c[i][1]<<" ";
			cout<<c[i][2]<<" ";
			cout<<c[i][3]<<endl;
			cout<<endl;

			if(process_point[i]==requ_seq[i][0])
			{
				*(process_completed+i)=0;
				for(r=1;r<requ_seq[i][0];r++)
				{
					s=requ_seq[i][r];
					release_resource(s,1);
                    *(*(resource_alloc+i)+s-1)=*(*(resource_alloc+i)+s-1)-1;
					
					

				}
                cout<<"进程"<<i+1<<"已经执行完毕"<<endl;
				cout<<endl;
			}
             for(t=0;t<6;t++)
			{
				if(*(process_completed+t)==2)
                *(process_completed+t)=1;
			}
            Sleep(rand()%500);
            process_point[i]++;
		}
		else *(process_completed+i)=2;
	}
}