磁盘调度
#include <iostream>
#include <math.h>
#include <stdlib.h>
#include <algorithm>
#include <cstring>
#include <windows.h>
#include <fstream>
using namespace std;
int position = 0; //当前磁道位置
int dis = 0;
double average_distance = 0;
void request(vector<int>&m_vec,ofstream &outfile){
cout<<"随机生成磁盘序列:"<<endl;
int n = 0;
srand(time(NULL)); //添加随机数种子
n = rand() % 20 + 1;
int temp = 0; 6
for(int i=0;i<n;i++){
temp = rand() % 100;
m_vec.push_back(temp);
cout<<temp<<" ";
outfile<<temp<<endl;
}
cout<<endl;
position = rand() % 100;
cout<<"当前磁道:"<<position<<endl;
}
void compute_dis(vector<int>m_vec,int &dis,double &average_distance){
average_distance = (double)dis / (double)m_vec.size();
}
void SCAN(vector<int>m_vec,int position){ //电梯调度算法
dis = 0;
average_distance = 0;
sort(m_vec.begin(),m_vec.end()); //从小到大排序
int i = 0;
for(vector<int>::iterator it=m_vec.begin();it!=m_vec.end();it++){
if(position >= *it)
i++; //找到position所在的磁道
}
int left = i - 1; //先从外到内扫描
int right = i;
while(left >= 0){
dis += abs(position - m_vec[left]);
Sleep(500);
cout<<"->"<<m_vec[left];
position = m_vec[left];
left --;
}
while(right < m_vec.size()){
dis += abs(position - m_vec[right]);
Sleep(500);
cout<<"->"<<m_vec[right];
position = m_vec[right];
right ++;
}
compute_dis(m_vec,dis,average_distance);
}
void CSCAN(vector<int>m_vec,int position){ //循环扫描算法
dis = 0;
average_distance = 0;
sort(m_vec.begin(),m_vec.end()); //从小到大排序
int i = 0;
for(vector<int>::iterator it=m_vec.begin();it!=m_vec.end();it++){
if(position >= *it)
i++; //找到position所在的磁道
}
int left = i - 1; //先从外到内扫描
int right = i;
while(left >= 0){
dis += abs(position - m_vec[left]);
Sleep(500);
cout<<"->"<<m_vec[left];
position = m_vec[left];
left --;
}
position = 100; //立即到最外侧的磁道
int len = m_vec.size()-1;
while(len >= right){
dis += abs(position - m_vec[len]);
Sleep(500);
cout<<"->"<<m_vec[len];
position = m_vec[len];
len --;
}
compute_dis(m_vec,dis,average_distance);
}
void print(){
cout<<endl<<endl;
cout<<"经计算,磁头移动的总距离为:"<<dis<<endl;
cout<<"磁头平均移动距离:"<<average_distance<<endl;
cout<<endl<<endl;
}
int choose_algorithm(vector<int>m_vec){
cout<<endl<<endl;
cout<<"本实验可用的调度算法有以下3种:"<<endl;
cout<<" 1.SCAN 2.CSCAN 3.结束本序列的调度 4.结束程序"<<endl;
int choice = 0;
cout<<"选择:"<<endl;
cin>>choice;
cout<<endl;
while(choice!=3 && choice!=4){
cout<<"磁盘请求的服务状况:"<<endl;
cout<<position;
switch(choice){
case 1:
SCAN(m_vec,position);break;
case 2:
CSCAN(m_vec,position);break;
default:
cout<<"******非法输入!******"<<endl<<endl;break;
}
if(choice<=4 && choice>=1)
print();
cout<<"选择:"<<endl;
cin>>choice;
}
if(choice == 4)
return 0;
else
cout<<endl<<endl;
return 1;
}
int main(){
cout<<"---------------磁盘调度算法模拟实验-----------------"<<endl;
ofstream outfile;
outfile.open("data.txt");
while(1){
vector<int> vec;
while(!vec.empty())
vec.pop_back();
request(vec,outfile); //请求服务序列
int flag = choose_algorithm(vec);
if(flag == 0)
break;
}
outfile.close();
return 0;
}