3. Shortest job first

#include <iostream>

using namespace std;

int main() {

    int A[100][4];

    int i, j, n, total = 0, index, temp;

    float avg_wt, avg_tat;

    cout << "Enter number of processes: ";

    cin >> n;

    cout << "Enter Burst Time:" << endl;

    for (i = 0; i < n; i++) {

        cout << "P" << i + 1 << ": ";

        cin >> A[i][1];

        A[i][0] = i + 1;

    }

    for (i = 0; i < n; i++) {

        index = i;

        for (j = i + 1; j < n; j++)

            if (A[j][1] < A[index][1])

                index = j;

        temp = A[i][1];

        A[i][1] = A[index][1];

        A[index][1] = temp;

        temp = A[i][0];

        A[i][0] = A[index][0];

        A[index][0] = temp;

    }

    A[0][2] = 0;

    for (i = 1; i < n; i++) {

        A[i][2] = 0;

        for (j = 0; j < i; j++)

            A[i][2] += A[j][1];

        total += A[i][2];

    }

    avg_wt = (float)total / n;

    total = 0;

    cout << "P\tBT\tWT\tTAT" << endl;

    for (i = 0; i < n; i++) {

        A[i][3] = A[i][1] + A[i][2];

        total += A[i][3];

        cout << "P" << A[i][0] << "\t" << A[i][1] << "\t" << A[i][2] << "\t" << A[i][3] << endl;

    }

    avg_tat = (float)total / n;

    cout << "Average Waiting Time= " << avg_wt << endl;

    cout << "Average Turnaround Time= " << avg_tat << endl;

}