SRTF(SJF-PREEMPTIVE)

#include <stdio.h>

int main() {
    int n, i, j, min_bt, time = 0, completed = 0, sum_wait = 0, sum_turnaround = 0;
    int at[10], bt[10], rt[10], p[10]; // Arrays for arrival times, burst times, remaining times, and process numbers
    int wait[10], turnaround[10]; // Arrays for waiting times and turnaround times
    float avg_wait, avg_turnaround;

    printf("Enter the number of processes: ");
    scanf("%d", &n);

    // Input arrival times and burst times for each process
    for (i = 0; i < n; i++) {
        printf("Enter the arrival time and burst time for process %d: ", i + 1);
        scanf("%d%d", &at[i], &bt[i]);
        rt[i] = bt[i]; // Initialize remaining time as burst time
        p[i] = i + 1; // Process numbers
    }

    // Initialize arrays for waiting and turnaround times
    for (i = 0; i < n; i++) {
        wait[i] = 0;
        turnaround[i] = 0;
    }

    printf("\nProcess\tAT\tBT\tWT\tTAT\n");

    while (completed != n) {
        // Find process with minimum remaining time at each time unit
        min_bt = 9999; // A large number to find the minimum burst time
        int shortest = -1; // Index of the process with the shortest remaining time

        for (i = 0; i < n; i++) {
            if (at[i] <= time && rt[i] > 0 && rt[i] < min_bt) {
                min_bt = rt[i];
                shortest = i;
            }
        }

        if (shortest == -1) {
            // No process is currently available to execute
            time++;
            continue;
        }

        rt[shortest]--; // Decrement the remaining time of the shortest process

        if (rt[shortest] == 0) {
            // Process is completed
            completed++;
            int end_time = time + 1; // Time at which the process completes
            turnaround[shortest] = end_time - at[shortest]; // Turnaround time
            wait[shortest] = turnaround[shortest] - bt[shortest]; // Waiting time
            sum_wait += wait[shortest];
            sum_turnaround += turnaround[shortest];

            printf("P[%d]\t%d\t%d\t%d\t%d\n", p[shortest], at[shortest], bt[shortest], wait[shortest], turnaround[shortest]);
        }

        time++; // Increment time
    }

    avg_wait = (float)sum_wait / (float)n;
    avg_turnaround = (float)sum_turnaround / (float)n;

    printf("Average waiting time is %.2f\n", avg_wait);
    printf("Average turnaround time is %.2f\n", avg_turnaround);

    return 0;
}