LOOK.cpp

/* LOOK algorithm : Same as SCAN but will go to the least request track and not till 0 
and then back from inside to outside servicing requests. This algorithm is simple and easy to 
understand. LOOK algorithm have no starvation. This algorithm is better than FCFS and SCAN 
Scheduling algorithm . */


//This code is contributed by Sourajita Dewasi
#include <iostream>
#include<stdio.h>
#include<algorithm>

using namespace std;
int last=0;
int first=0;
int loc,count, i, j, temp,seek, head_indice, least_indice, Cylinder;
int seek1=0;

int LOOK(int arr[], int n, int head){
    int arr1[6];
    int distance=0;
    arr1[5]=head;
    for(i=0; i<n; i++){
        arr1[i]=arr[i];
    }
    sort(arr1,arr1+6);
    for(int i=0; i<6; i++){
        if(arr1[i]==head){
            head_indice=i;
        }
        if(arr[i]==0){
            least_indice=i;
        }
    }  
    //Going outside the track
    for(i=head_indice+1; i<6; i++){
        distance=arr1[i]-head;
        seek=seek+distance;
        head=arr1[i];
        cout<<"\n Next address is "<<head;
    }
        //Going inside the track
    for( i=head_indice-1; i>=0; i--){
        distance=head-arr1[i];
        seek=seek+distance;
        head=arr1[i];
        cout<<"\n Next address is "<<head;
    }
    
    seek1=(arr1[5]-arr1[head_indice]) + (arr1[5]-arr1[0]);
    return seek1;
    }
    

int main() {
	int Request[5]={23,89,132,42,187}; //Request Array
	Cylinder=LOOK(Request, 5, 100); //Initially head is at 100
	cout<<"\n Total no of seeks "<<Cylinder;
	return 0;
}