RES.c

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;
+}

Preemptive Scheduling Algorithm/Readme.md

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+# Ripple Effect Scheduling (RES) Algorithm in C
+
+This project implements the **Ripple Effect Scheduling (RES)** algorithm in C, a priority-based scheduling algorithm that minimizes disruptions to lower-priority tasks. This algorithm sorts tasks based on their priority and calculates waiting and turnaround times for each process. Additionally, it applies a "ripple effect" adjustment to reduce the waiting time of lower-priority tasks.
+
+## Table of Contents
+
+1. [Overview](#overview)
+2. [Algorithm Details](#algorithm-details)
+3. [Code Structure](#code-structure)
+4. [How to Use](#how-to-use)
+5. [Sample Input/Output](#sample-inputoutput)
+
+## Overview
+
+The Ripple Effect Scheduling (RES) algorithm is a **priority-based CPU scheduling algorithm** that aims to:
+- Prioritize tasks based on their priority level (where a lower priority number indicates higher priority).
+- Minimize disruptions to lower-priority tasks using a "ripple effect" adjustment, where each process slightly adjusts the waiting time of the next lower-priority process.
+
+This approach ensures that high-priority tasks are executed first but avoids causing excessive delays for lower-priority tasks.
+
+## Algorithm Details
+
+The algorithm involves the following steps:
+
+1. **Sorting by Priority**: Processes are sorted by priority (ascending order), where a lower priority number indicates a higher priority.
+2. **Waiting Time Calculation**:
+   - For each process, calculate the waiting time as the cumulative burst time of previous processes.
+   - Apply the "ripple effect" by reducing the waiting time of the next process slightly if it has a lower priority, ensuring it doesn't fall below zero.
+3. **Turnaround Time Calculation**:
+   - For each process, calculate the turnaround time as the sum of waiting time and burst time.
+4. **Average Waiting and Turnaround Times**: Display the average waiting and turnaround times for all processes.
+
+## Code Structure
+
+- **`Process` struct**: Stores the details for each process, including `id`, `priority`, `burstTime`, `waitingTime`, and `turnaroundTime`.
+- **`rippleEffectScheduling()`**: Sorts processes by priority and calculates waiting and turnaround times, applying the ripple effect.
+- **`printProcesses()`**: Displays the process details in a tabular format and calculates average waiting and turnaround times.
+- **`main()`**: Collects user input for each process and invokes the scheduling functions.
+
+## How to Use
+
+1. Clone or download this repository to your local machine.
+2. Compile the code using a C compiler (instructions below).
+3. Run the executable and input the number of processes.
+4. For each process, enter the priority and burst time when prompted.
+
+The output will display the waiting time and turnaround time for each process, along with the average waiting and turnaround times.
+
+## Sample Input/Output
+
+### Sample Input
+
+Enter number of processes: 3
+Enter priority and burst time for process 1: 1 5
+Enter priority and burst time for process 2: 2 8
+Enter priority and burst time for process 3: 1 2
+
+### Sample Output
+
+ID      Priority    Burst Time      Waiting Time    Turnaround Time
+1       1           5               0               5
+3       1           2               5               7
+2       2           8               4               12
+
+Average Waiting Time: 3.00
+Average Turnaround Time: 8.00