银行家算法用文件输入输出实现
时间: 2023-12-06 10:37:44 浏览: 111
银行家算法可以通过文件输入输出实现,具体步骤如下:
1.首先,需要建立银行家算法的数据结构描述,包括进程数、资源数、可用资源数、已分配资源数、需求资源数等信息。
2.将初始数据放在文件中,算法运行时读出。可以使用Python中的open()函数打开文件,使用read()函数读取文件内容,并使用split()函数将文件内容分割成需要的数据结构。
3.对给定的资源请求,使用算法判断是否允许。可以使用Python中的if语句判断请求是否合法,并根据算法的判断结果输出相应的信息。
4.输出每次判断产生的执行序列。可以使用Python中的print()函数输出每次判断的执行序列。
下面是一个简单的Python实现示例:
```python
# 读取文件中的数据
with open('data.txt', 'r') as f:
data = f.read().split('\n')
process_num = int(data[0])
resource_num = int(data[1])
available = list(map(int, data[2].split()))
max_claim = [list(map(int, data[i].split())) for i in range(3, 3+process_num)]
allocation = [list(map(int, data[i].split())) for i in range(3+process_num, 3+2*process_num)]
need = [[max_claim[i][j] - allocation[i][j] for j in range(resource_num)] for i in range(process_num)]
# 判断资源请求是否合法
def is_safe(process_id, request):
global available, allocation, need
for i in range(resource_num):
if request[i] > need[process_id][i] or request[i] > available[i]:
return False
return True
# 处理资源请求
def request_resource(process_id, request):
global available, allocation, need
if is_safe(process_id, request):
for i in range(resource_num):
available[i] -= request[i]
allocation[process_id][i] += request[i]
need[process_id][i] -= request[i]
return True
else:
return False
# 输出每次判断产生的执行序列
def print_sequence():
global available, allocation, need
sequence = []
work = available.copy()
finish = [False] * process_num
while False in finish:
flag = False
for i in range(process_num):
if not finish[i] and all([need[i][j] <= work[j] for j in range(resource_num)]):
sequence.append(i)
for j in range(resource_num):
work[j] += allocation[i][j]
finish[i] = True
flag = True
if not flag:
return []
return sequence
# 处理资源请求并输出执行序列
request = [1, 0, 2]
if request_resource(0, request):
print("Request is granted.")
print("Execution sequence:", print_sequence())
else:
print("Request is denied.")
```