test_fcfs.js

// Test FCFS algorithm manually
const processes = [
  { pid: 'P1', arrivalTime: 0, burstTime: 5, priority: 2 },
  { pid: 'P2', arrivalTime: 1, burstTime: 3, priority: 1 },
  { pid: 'P3', arrivalTime: 2, burstTime: 8, priority: 4 },
  { pid: 'P4', arrivalTime: 3, burstTime: 6, priority: 3 },
];

// Manually trace FCFS
const results = {};
processes.forEach(p => {
  results[p.pid] = {
    arrivalTime: p.arrivalTime,
    burstTime: p.burstTime,
    completionTime: 0,
    turnaroundTime: 0,
    waitingTime: 0,
    responseTime: -1,
  };
});

// Sort by arrival
const arrivals = [...processes].sort((a, b) => a.arrivalTime - b.arrivalTime);
console.log('Arrival order:', arrivals.map(p => `${p.pid}: ${p.arrivalTime}`));

let time = 0;
let completed = 0;
const ganttChart = [];

// FCFS execution
for (let i = 0; i < arrivals.length; i++) {
  const proc = arrivals[i];
  
  // If process arrives after current time, advance time
  if (time < proc.arrivalTime) {
    time = proc.arrivalTime;
  }
  
  const ganttStart = time;
  results[proc.pid].responseTime = time - proc.arrivalTime;
  
  // Execute
  time += proc.burstTime;
  
  ganttChart.push({ pid: proc.pid, start: ganttStart, end: time });
  results[proc.pid].completionTime = time;
  results[proc.pid].turnaroundTime = time - proc.arrivalTime;
  results[proc.pid].waitingTime = results[proc.pid].turnaroundTime - proc.burstTime;
  
  console.log(`${proc.pid}: Start=${ganttStart}, End=${time}, Response=${results[proc.pid].responseTime}, Turnaround=${results[proc.pid].turnaroundTime}, Waiting=${results[proc.pid].waitingTime}`);
}

console.log('\nGantt Chart:', ganttChart);
console.log('Total Time:', time);

// Calculate averages
const avgTurnaround = Object.values(results).reduce((sum, p) => sum + p.turnaroundTime, 0) / 4;
const avgWaiting = Object.values(results).reduce((sum, p) => sum + p.waitingTime, 0) / 4;
const avgResponse = Object.values(results).reduce((sum, p) => sum + p.responseTime, 0) / 4;

console.log('\nAverages:');
console.log('Avg Turnaround:', avgTurnaround);
console.log('Avg Waiting:', avgWaiting);
console.log('Avg Response:', avgResponse);