priority.c

#include <stdio.h>

void priorityScheduling(int n, int arrival[], int burst[], int priority[]) {
    int remaining[n], completion[n], waiting[n], turnaround[n];
    int time = 0, completed = 0, processOrder[100], ganttTime[100], index = 0;
    int isCompleted[n];

    for (int i = 0; i < n; i++) {
        remaining[i] = burst[i];
        isCompleted[i] = 0;
    }

    while (completed < n) {
        int minPriority = 9999, minIndex = -1;

        // Find the process with the highest priority (lower number = higher priority)
        for (int i = 0; i < n; i++) {
            if (arrival[i] <= time && remaining[i] > 0 && priority[i] < minPriority) {
                minPriority = priority[i];
                minIndex = i;
            }
        }

        if (minIndex == -1) {
            // If no process is available, move forward in time without adding idle to Gantt chart
            time++;
            continue;
        }

        // Store execution in Gantt chart order
        if (index == 0 || processOrder[index - 1] != minIndex + 1) {
            processOrder[index] = minIndex + 1;
            ganttTime[index] = time;
            index++;
        }

        remaining[minIndex]--;
        time++;

        if (remaining[minIndex] == 0) {
            completion[minIndex] = time;
            turnaround[minIndex] = completion[minIndex] - arrival[minIndex];
            waiting[minIndex] = turnaround[minIndex] - burst[minIndex];
            isCompleted[minIndex] = 1;
            completed++;
        }
    }

    // Print Process Table
    printf("\nPID\tArrival\tBurst\tPriority\tWaiting\tTurnaround\n");
    for (int i = 0; i < n; i++)
        printf("P%d\t%d\t%d\t%d\t\t%d\t%d\n", i + 1, arrival[i], burst[i], priority[i], waiting[i], turnaround[i]);

    // Printing Gantt Chart in a Box Format
    printf("\nGantt Chart:\n ");

    // Top Border
    for (int i = 0; i < index; i++) {
        printf("+----");
    }
    printf("+\n");

    // Process Row
    for (int i = 0; i < index; i++) {
        printf("| P%d ", processOrder[i]);
    }
    printf("|\n");

    // Bottom Border
    for (int i = 0; i < index; i++) {
        printf("+----");
    }
    printf("+\n");

    // Time Labels
    printf("%d", ganttTime[0]); // Start time of the first process
    for (int i = 1; i < index; i++) {
        printf("    %d", ganttTime[i]);
    }
    printf("   %d\n", time); // End time of the last process
}

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

    int arrival[n], burst[n], priority[n];

    for (int i = 0; i < n; i++) {
        printf("Enter arrival time, burst time, and priority for process %d: ", i + 1);
        scanf("%d %d %d", &arrival[i], &burst[i], &priority[i]);
    }

    priorityScheduling(n, arrival, burst, priority);
    return 0;
}