操作系统之银行家算法

#include<bits/stdc++.h>
using namespace std;
int n,m,rr,num,f[105],work[105],Request[105][105],workseque[105][105],finish[105],Source[105],
	Available[105],Max[105][105],Allocation[105][105],Need[105][105];
void print(){
	printf("-------------------------资源分配情况-------------------------\n");
	printf("            Max        Allocation       Need       Available\n");
	printf("进程ID    ");
	for(int i = 0;i < 4;i++){
		for(int j = 0;j < m;j++)
			!j ? printf("%c",'A' + j) : printf("  %c",'A' + j);
		printf("       ");
	}
	printf("\n");
	for(int i = 0;i < n;i++){
	    printf("   %d    ",i);
        for(int j = 0;j < m;j++)
            printf("%3d",Max[i][j]);
        printf("     ");
        for(int j = 0;j < m;j++)
            printf("%3d",Allocation[i][j]);
        printf("     ");
        for(int j = 0;j < m;j++)
            printf("%3d",Need[i][j]);
        if(!i){
            printf("     ");
            for(int j = 0;j < m;j++)
                printf("%3d",Available[j]);
        }
        printf("\n");
	}
	printf("--------------------------------------------------------------\n");
	return;
}
void input(int a[][105]){
	for(int i = 0;i < n;i++)//进程个数
		for(int j = 0;j < m;j++)//资源数目
			scanf("%d",&a[i][j]);
	return;
}
//可用资源矩阵
void available(){
    int a;
    for(int i = 0;i < m;i++){
        a = 0;
        for(int j = 0;j < n;j++)
            a += Allocation[j][i];
        Available[i] = Source[i] - a;
    }
    return;
}
int IsSecurity(){
	int cnt,fx,flag,flag1,index,index1;
	memset(finish,false,sizeof(finish));
	for(int i = 0;i < m;i++){
        work[i] = Available[i];
        workseque[0][i] = work[i];
	}
	index = 0,flag1 = 0,index1 = 0,cnt = 0;
	while(1){
		for(int i = 0;i < n;i++){//安全性算法
			flag = 0;
			for(int k = 0;k < m;k++){
				if(!finish[i] && Need[i][k] <= work[k])
					flag = 1;
				else
					break;
			}
			if(flag){
                index1++;
				f[index++] = i;//把第i个进程保存到f数组中
				finish[i] = true;
				for(int k = 0;k < m;k++){
                    work[k] += Allocation[i][k];
                    workseque[index1][k] = work[k];
				}
			}
		}
		if((index + 1) > n){
			flag1 = 1;
			break;
		}
	}
	cout << endl;
	for(int j = 0;j < n;j++){
        fx = 1;
        for(int k = 0;k < m;k++)
            if(Available[k] < Need[j][k]){
                fx = 0;
                break;
            }
        if(!fx)
            cnt++;
    }
    if(cnt == n){
        printf("已经不满足任何进程的需要,故系统进入不安全状态,此时系统不分配资源！！\n");
        return 2;
    }
    else if(flag1){
		printf("系统存在一个安全序列:");
		for(int i = 0;i < index;i++)
			cout << f[i] << " ";
		printf("\n");
	}
	else
        return 0;
    return 1;
}
void print2(){
	printf("-------------------------安全性序列表-------------------------------------\n");
    printf("            Work          Need      Allocation  Work+Allocation   Finish\n");
	printf("进程ID    ");
	for(int i = 0;i < 4;i++){
		for(int j = 0;j < m;j++)
			!j ? printf("%c",'A' + j) : printf("  %c",'A' + j);
		printf("       ");
	}
	cout << endl;
	for(int i = 0;i < n;i++){
        printf("   %d    ",f[i]);
        for(int j = 0;j < m;j++)
            printf("%3d",workseque[i][j]);
        printf("     ");
        for(int j = 0;j < m;j++)
            printf("%3d",Need[f[i]][j]);
        printf("     ");
        for(int j = 0;j < m;j++)
            printf("%3d",Allocation[f[i]][j]);
        printf("     ");
        for(int j = 0;j < m;j++)
            printf("%3d",workseque[i + 1][j]);
        printf("        true");
        printf("\n");

	}
	printf("--------------------------------------------------------------------------\n");
	return;
}
int request(){
    int flag,res;
    flag = 1;
    for(int i = 0;i < m;i++)
        if((Request[rr][i] > Need[rr][i]) || (Request[rr][i] > Available[i])){
            flag = 0;
            break;
        }
    if(!flag){
        printf("不能分配资源,进程等待\n");
        return 0;
    }
    ///修改变量的值
    for(int i = 0;i < m;i++){
        Allocation[rr][i] += Request[rr][i];
        Need[rr][i] -= Request[rr][i];
        Available[i] -= Request[rr][i];
    }
    res = IsSecurity();
    if(res){
        if(res == 2)
            return 1;
        else{
            print2();
            return 0;
        }
    }
    else{
        for(int i = 0;i < m;i++){
            Allocation[rr][i] -= Request[rr][i];
            Need[rr][i] += Request[rr][i];
            Available[i] += Request[rr][i];
        }
        printf("不存在安全性序列表,让进程等待！\n");
        return 0;
    }
    return 0;
}
int main(){
	printf("请输入进程的个数(n):\n");
	scanf("%d",&n);
	printf("请输入资源的数目(m):\n");
	scanf("%d",&m);
	printf("请输入每种资源的最大数量:(0 - m)\n");
	for(int i = 0;i < m;i++)
		scanf("%d",&Source[i]);
	printf("请输入每个进程需要的最大资源数目Max[i][j]:\n");
	input(Max);
	printf("请输入已经分配给每个进程的资源数目Allocation[i][j]:\n");
	input(Allocation);
	//Need矩阵
	for(int i = 0;i < n;i++)
        for(int j = 0;j < m;j++)
            Need[i][j] = Max[i][j] - Allocation[i][j];
    //分配矩阵
    available();
    print();//打印
    //安全性算法
    if(IsSecurity())
        print2();//打印安全序列表
    //分配资源
    for(int i = 0;;i++){
        printf("\n\n--------------第%d次分配--------------------\n",i + 1);
        printf("请输入请求资源的编号:\n");
        scanf("%d",&rr);
        printf("请输入请求的每种资源的数目:\n");
        for(int j = 0;j < m;j++)
            scanf("%d",&Request[rr][j]);
        if(request())//分配资源算法
            return 0;
    }
	return 0;
}

运行截图