RES.c

Author: AshmitaBarthwal

Preemptive Scheduling Algorithm/RES.c

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+#include <stdio.h>
+#include <stdlib.h>
+
+#define MAX_PROCESSES 10
+
+// Define a structure for processes
+typedef struct {
+    int id;
+    int priority;      // Lower number means higher priority
+    int burstTime;
+    int waitingTime;
+    int turnaroundTime;
+} Process;
+
+// Function to perform Ripple Effect Scheduling (RES)
+void rippleEffectScheduling(Process processes[], int n) {
+    // Sort processes by priority (ascending order for higher priority first)
+    for (int i = 0; i < n - 1; i++) {
+        for (int j = i + 1; j < n; j++) {
+            if (processes[i].priority > processes[j].priority) {
+                Process temp = processes[i];
+                processes[i] = processes[j];
+                processes[j] = temp;
+            }
+        }
+    }
+
+    // Initialize waiting time for the first process
+    processes[0].waitingTime = 0;
+
+    // Calculate waiting time for each process
+    for (int i = 1; i < n; i++) {
+        processes[i].waitingTime = processes[i - 1].waitingTime + processes[i - 1].burstTime;
+
+        // Ripple effect: give small wait reduction to next lower-priority process
+        if (i < n - 1 && processes[i].priority < processes[i + 1].priority) {
+            processes[i + 1].waitingTime -= processes[i + 1].priority - processes[i].priority;
+            if (processes[i + 1].waitingTime < 0) {
+                processes[i + 1].waitingTime = 0; // Avoid negative waiting time
+            }
+        }
+    }
+
+    // Calculate turnaround time for each process
+    for (int i = 0; i < n; i++) {
+        processes[i].turnaroundTime = processes[i].waitingTime + processes[i].burstTime;
+    }
+}
+
+// Function to print process details
+void printProcesses(Process processes[], int n) {
+    float totalWaitingTime = 0, totalTurnaroundTime = 0;
+
+    printf("ID\tPriority\tBurst Time\tWaiting Time\tTurnaround Time\n");
+    for (int i = 0; i < n; i++) {
+        totalWaitingTime += processes[i].waitingTime;
+        totalTurnaroundTime += processes[i].turnaroundTime;
+        printf("%d\t%d\t\t%d\t\t%d\t\t%d\n", 
+               processes[i].id, processes[i].priority, 
+               processes[i].burstTime, processes[i].waitingTime, 
+               processes[i].turnaroundTime);
+    }
+
+    printf("\nAverage Waiting Time: %.2f\n", totalWaitingTime / n);
+    printf("Average Turnaround Time: %.2f\n", totalTurnaroundTime / n);
+}
+
+int main() {
+    Process processes[MAX_PROCESSES];
+    int n;
+
+    printf("Enter number of processes: ");
+    scanf("%d", &n);
+
+    // Input details for each process
+    for (int i = 0; i < n; i++) {
+        processes[i].id = i + 1;
+        printf("Enter priority and burst time for process %d: ", i + 1);
+        scanf("%d %d", &processes[i].priority, &processes[i].burstTime);
+    }
+
+    // Perform Ripple Effect Scheduling
+    rippleEffectScheduling(processes, n);
+
+    // Print process details and average times
+    printProcesses(processes, n);
+
+    return 0;
+}