这周课程设计,以为会很好玩,实验书发下来,居然只是实现银行家算法,失望了……用了小半天时间(原谅我上过操作系统居然连银行家算法是什么都忘了,只能回去看书重来),用golang简单实现了银行家算法,一下是代码:
package main
import (
"fmt"
"log"
"os"
)
var Available []int //可以用资源向量
var Max [][]int //最大需求矩阵
var Allocation [][]int //已分配矩阵
var Need [][]int //需求矩阵
var Request []int //请求向量
var Work []int //工作向量
var Finish []bool //Finish向量
var pid int //请求资源进程号
var serial []int //用于存储安全序列
var work [][]int
//初始化
func init() {
//资源数量为10,5,7
//资源数量为10,5,7
}
//银行家算法
func Bank() {
for i := 0; i < len(Request); i++ {
if Request[i] <= Need[pid][i] {
continue
} else {
log.Fatalln("所需资源超过宣布最大值")
}
}
for i := 0; i < len(Request); i++ {
if Request[i] <= Available[i] {
continue
} else {
log.Fatalln("尚无足够资源,需等待")
}
}
for i := 0; i < len(Available); i++ {
Available[i] = Available[i] - Request[i]
}
for i := 0; i < len(Allocation[0]); i++ {
Allocation[pid][i] = Allocation[pid][i] + Request[i]
}
for i := 0; i < len(Need[0]); i++ {
Need[pid][i] = Need[pid][i] - Request[i]
}
if Safe() {
fmt.Println("完成分配")
} else {
fmt.Println("系统处于不安全状态,等待")
}
fmt.Println("Max:", Max)
fmt.Println("Allocation:", Allocation)
fmt.Println("Need:", Need)
fmt.Println("Available:", Available)
fmt.Println("Work:", work)
fmt.Println("安全序列:", serial)
}
//安全性检查
func Safe() bool {
Work = Available
for i := 0; i < len(Max); i++ {
Finish = append(Finish, false)
}
temp := 0
step2:
for i := temp; i < len(Finish); i++ {
if Finish[i] == false {
for j := 0; j < len(Work); j++ {
if Need[i][j] <= Work[j] {
if j == len(Work)-1 {
serial = append(serial, i)
work = append(work, Work)
for j := 0; j < len(Work); j++ {
Work[j] = Work[j] + Allocation[i][j]
}
Finish[i] = true
if i == len(Finish)-1 {
temp = 0
} else {
temp = i + 1
}
goto step2
}
} else {
break
}
}
} else {
continue
}
if i == len(Finish)-1 {
return false
}
}
return true
}
func main() {
lable:
var sel int
fmt.Println("********************银行家算法********************")
fmt.Println()
fmt.Println("\t1、测试数据一")
fmt.Println("\t2、测试数据二")
fmt.Println("\t3、测试数据三")
fmt.Println("\t4、退出")
fmt.Println()
fmt.Println("************************************************")
fmt.Print("请做出你的选择:")
fmt.Scanln(&sel)
switch sel {
//资源总数量为10,5,7
case 1:
//测试数据1
Available = []int{3, 3, 2}
Max = [][]int{{7, 5, 3}, {3, 2, 2}, {9, 0, 2}, {2, 2, 2}, {4, 3, 3}}
Allocation = [][]int{{0, 1, 0}, {2, 0, 0}, {3, 0, 2}, {2, 1, 1}, {0, 0, 2}}
Need = [][]int{{7, 4, 3}, {1, 2, 2}, {6, 0, 0}, {0, 1, 1}, {4, 3, 1}}
Request = []int{1, 0, 2}
pid = 1
case 2:
//测试数据2
Available = []int{2, 3, 0}
Max = [][]int{{7, 5, 3}, {3, 2, 2}, {9, 0, 2}, {2, 2, 2}, {4, 3, 3}}
Allocation = [][]int{{0, 1, 0}, {3, 0, 2}, {3, 0, 2}, {2, 1, 1}, {0, 0, 2}}
Need = [][]int{{7, 4, 3}, {0, 2, 0}, {6, 0, 0}, {0, 1, 1}, {4, 3, 1}}
Request = []int{3, 3, 0}
pid = 4
case 3:
//测试数据3
Available = []int{2, 3, 0}
Max = [][]int{{7, 5, 3}, {3, 2, 2}, {9, 0, 2}, {2, 2, 2}, {4, 3, 3}}
Allocation = [][]int{{0, 1, 0}, {3, 0, 2}, {3, 0, 2}, {2, 1, 1}, {0, 0, 2}}
Need = [][]int{{7, 4, 3}, {0, 2, 0}, {6, 0, 0}, {0, 1, 1}, {4, 3, 1}}
Request = []int{0, 2, 0}
pid = 0
case 4:
os.Exit(0)
default:
fmt.Println("没有此选项")
}
//执行银行家算法
Bank()
goto lable
}
很简陋,只测试了三组数据,如果发现bug,望斧正,谢谢!
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