电梯优先调度算法_电梯调度算法
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电梯优先调度算法
电梯调度算法(ms InterView)
移臂调度算法包括以下四种：
1）先来先服务算法：根据访问者提出访问请求的先后次序来决定执行次序。
2）最短寻找时间优先调度算法：从等待的访问者中挑选寻找时间最短的那个请求执行，而不管访问者的先后次序。
3）电梯调度扫描算法：从移动臂当前位置沿移动方向选择最近的那个柱面的访问者来执行，若该方向上无请求访问时，就改变移动方向再选择。
4）单向扫描调度算法：从0柱面开始往里单向扫描，扫到哪个执行哪个。
*/
// t1.cpp : 定义控制台应用程序的入口点。
//
#include “stdafx.h” #include“math.h” #include“stdlib.h” #include“string.h” struct Head {
int nPosition;bool bVisited;};
void Visit(struct Head *pHead){
printf(“visite cy:%dn”,pHead->nPosition);pHead->bVisited=true;} int ReadInputKeyboard(struct Head *pHead,int *pCurrentPosition,int nMaxNumber){ int i;
printf(“please input Current position:”);scanf(“%d”,pCurrentPosition);
printf(“please input will visit position:”);for(i=0;i
scanf(“%d”,&pHead[i].nPosition);pHead[i].bVisited=false;if(pHead[i].nPosition
Head
*pHead,int
*pCurrentPosition,int nMaxNumber){ int i;
char szFileName[256],*q,*p,szTemp[20];printf(“please input filename:”);scanf(“%s”,szFileName);
FILE *pFile=fopen(szFileName,“r”);if(pFile==NULL){
printf(“open file %s error”,szFileName);return-1;}
for(i=0;!feof(pFile)&&i
p=szFileName;fgets(p,256,pFile);
while(q=strchr(p,',')){
memset(szTemp,0,sizeof(szTemp)*sizeof(char));strncpy(szTemp,p,q-p);p=q+1;if(i==0)
*pCurrentPosition=atoi(szTemp);else { pHead[i-1].nPosition=atoi(szTemp);pHead[i-1].bVisited=false;} i++;}
memset(szTemp,0,sizeof(szTemp)*sizeof(char));pHead[i-1].nPosition=atoi(p);pHead[i-1].bVisited=false;//i++;
}
fclose(pFile);return i;}
int FifoVisit(int nCurrentPosition,struct Head *pHead,int nNumber){
//先来先服务
int nHaveVisited=0;int nMoveDistance=0;int i;while(nHaveVisited
for(i=0;i
if(pHead[i].bVisited)continue;
Visit(&pHead[i]);nHaveVisited++;
nMoveDistance+=abs(nCurrentPosition-pHead[i].nPosition);nCurrentPosition=pHead[i].nPosition;} }
printf(“the sum of move distance:%dn”,nMoveDistance);return nMoveDistance;}
int SsfoVisit(int nCurrentPosition,struct Head *pHead,int nNumber){ // 最短寻找时间优先
int nHaveVisited=0;int nMoveDistance=0;int nMinDistance=0;int nMinIndex=0;int i;
while(nHaveVisited
nMinDistance=0xffff;nMinIndex=0;//找最小值
for(i=0;i
if(pHead[i].bVisited)continue;
if(nMinDistance>abs(pHead[i].nPosition-nCurrentPosition)){
nMinDistance=abs(pHead[i].nPosition-nCurrentPosition);nMinIndex=i;} } //访问
Visit(&pHead[nMinIndex]);nHaveVisited++;
nMoveDistance+=nMinDistance;
nCurrentPosition=pHead[nMinIndex].nPosition;}
printf(“the sum of move distance:%dn”,nMoveDistance);return nMoveDistance;}
int DtVisit(int nCurrentPosition,bool bOut,struct Head *pHead,int nNumber){
//电梯调度算法
int nHaveVisited=0;int nMoveDistance=0;int nMinDistance=0;int nMinIndex=0;int i;
while(nHaveVisited
nMinDistance=0xffff;nMinIndex=0;//找最小值
for(i=0;i
if(pHead[i].bVisited)continue;
if(bOut&&pHead[i].nPositionnCurrentPosition){
if(nMinDistance>abs(pHead[i].nPosition-nCurrentPosition)){
nMinDistance=abs(pHead[i].nPosition-nCurrentPosition);nMinIndex=i;} } }
if(nMinDistance==0xffff){
bOut=!bOut;continue;}
//访问
Visit(&pHead[nMinIndex]);nHaveVisited++;
nMoveDistance+=nMinDistance;
nCurrentPosition=pHead[nMinIndex].nPosition;}
printf(“the sum of move distance:%dn”,nMoveDistance);return nMoveDistance;}
int DxVisit(int nCurrentPosition,struct Head *pHead,int nNumber){
//单向调度算法
int nHaveVisited=0;int nMoveDistance=0;int nMinDistance=0;int nMinIndex=0;int i;while(nHaveVisited
nMinDistance=0xffff;nMinIndex=0;//找最小值
for(i=0;i
if(pHead[i].bVisited)continue;
if(pHead[i].nPosition>nCurrentPosition){
if(nMinDistance>abs(pHead[i].nPosition-nCurrentPosition)){
nMinDistance=abs(pHead[i].nPosition-nCurrentPosition);nMinIndex=i;} } }
if(nMinDistance==0xffff){
nMoveDistance+=199-nCurrentPosition;nCurrentPosition=0;continue;}
//访问
Visit(&pHead[nMinIndex]);nHaveVisited++;
nMoveDistance+=nMinDistance;
nCurrentPosition=pHead[nMinIndex].nPosition;}
printf(“the sum of move distance:%dn”,nMoveDistance);return nMoveDistance;}
int main(int argc, char* argv[]){ //p114 struct Head mylist[20];//={98,false,183,false,37,false,122,false,14,false,124,false,65,false,67,false};
//int nCurrentPosition=53;
//int nRealNumber=8;
int nCurrentPosition=0;
int nRealNumber=ReadInputFile(mylist,&nCurrentPosition,20);// FifoVisit(nCurrentPosition,mylist,nRealNumber);
// SsfoVisit(nCurrentPosition,mylist,nRealNumber);
//DtVisit(nCurrentPosition,false,mylist,nRealNumber);
DxVisit(nCurrentPosition,mylist,nRealNumber);
return 0;}
