CPU Scheduling Simulator (C++)

This project is a terminal-based CPU scheduling simulator implemented in C++.
It is built to understand and compare how different CPU scheduling algorithms behave when applied to the same set of processes.

The program executes multiple scheduling algorithms in a single run so that their execution order, waiting time, and turnaround time can be compared directly.

Scheduling Algorithms Implemented

The simulator implements the following CPU scheduling algorithms:

• FCFS (First Come First Serve – Non-Preemptive)
  Processes are executed strictly in the order in which they arrive and are not interrupted once execution starts.

• SJF (Shortest Job First – Non-Preemptive)
  From the available processes, the one with the smallest burst time is selected and executed until completion.

• SRTF (Shortest Remaining Time First – Preemptive)
  At every time unit, the process with the shortest remaining burst time is chosen.
  The currently running process may be preempted if a shorter job arrives.

• Round Robin (Preemptive – Time Quantum = 2)
  Each process is given a fixed CPU time slice of 2 units.
  If the process does not complete within this time, it is placed back into the ready queue.

All algorithms run on the same predefined process set to ensure consistent comparison.

Process Model

Each process is defined using:

• Process ID (PID)
• Arrival Time
• Burst Time

During execution, the simulator computes:

• Completion Time (CT)
• Turnaround Time (TAT = CT − Arrival Time)
• Waiting Time (WT = TAT − Burst Time)

These values follow standard operating system definitions.

Scheduling Approach

• Non-preemptive algorithms execute a process continuously once selected.
• Preemptive algorithms are simulated one time unit at a time.
• Execution is tracked using a timeline to correctly represent preemption and context switching.
• Gantt charts are generated directly from the execution timeline to preserve correct ordering and timing.

Project Structure

process-scheduler/
├── src/
│   ├── main.cpp
│   ├── scheduler.cpp
│   ├── scheduler.h
│   └── process.h

How to Compile and Run

From the project root directory:

g++ src/main.cpp src/scheduler.cpp -o scheduler
./scheduler