# Program to simulate LOOK Disk Scheduling Algorithm

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While fulfilling requests similarly to the SCAN algorithm, the LOOK algorithm additionally “looks” ahead as though there are other tracks that need to be served in the same direction. The head changes course and begins servicing requests in the opposite direction if there are no pending requests in the direction it is traveling.

``````#include <stdio.h>
#include <stdlib.h>
int main(){
int RQ, i, j, n, TotalHeadMoment = 0, initial, size, move;
printf("Enter the number of Requests\n");
scanf("%d", &n);
printf("Enter the Requests sequence\n");
for (i = 0; i < n; i++)
scanf("%d", &RQ[i]);
printf("Enter initial head position\n");
scanf("%d", &initial);
printf("Enter total disk size\n");
scanf("%d", &size);
printf("Enter the head movement direction for high 1 and for low 0\n");
scanf("%d", &move);
for (i = 0; i < n; i++){
for (j = 0; j < n - i - 1; j++){
if (RQ[j] > RQ[j + 1]){
int temp;
temp = RQ[j];
RQ[j] = RQ[j + 1];
RQ[j + 1] = temp;
}
}
}
int index;
for (i = 0; i < n; i++){
if (initial < RQ[i]){
index = i;
break;
}
}
if (move == 1){
for (i = index; i < n; i++){
TotalHeadMoment = TotalHeadMoment + abs(RQ[i] - initial);
initial = RQ[i];
}
for (i = index - 1; i >= 0; i--){
TotalHeadMoment = TotalHeadMoment + abs(RQ[i] - initial);
initial = RQ[i];
}
}
else{
for (i = index - 1; i >= 0; i--){
TotalHeadMoment = TotalHeadMoment + abs(RQ[i] - initial);
initial = RQ[i];
}
for (i = index; i < n; i++){
TotalHeadMoment = TotalHeadMoment + abs(RQ[i] - initial);
initial = RQ[i];
}
}
printf("Total head movement is %d \n", TotalHeadMoment);
return 0;
}
``````

OUTPUT Learn about: Operating System

Source code on GitHub: https://github.com/CodewithSudeep/operating-system-c-program

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