21 Program for Banker's Algorithm in Operating System ~ Coding Atharva

Program:
 
#include <iostream>
using namespace std;

int n, m;

void display(int mat[5][3])
{
    for (int i = 0; i < n; i++)
    {
        cout << endl;
        for (int j = 0; j < m; j++)
        {
            cout << mat[i][j] << " ";
        }
    }
}

int main()
{
    cout << "\n\n Enter number of process:";
    cin >> n;

    cout << "\n\n Enter number of resources:";
    cin >> m;

    int alloc[n][3], need[n][3], max[n][3];
    int available[m];

    cout << "\n\n Enter Allocation Matrix:";
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < m; j++)
        {
            cin >> alloc[i][j];
        }
    }

    cout << "\n\n Enter Max Matrix:";
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < m; j++)
        {
            cin >> max[i][j];
        }
    }

    cout << "\n\n Enter available Array:";
    for (int i = 0; i < m; i++)
    {
        cin >> available[i];
    }

    cout << "\n\n Displaying Allocation Matrix:";
    display(alloc);

    cout << "\n\n Displaying Max Matrix:";
    display(max);

    cout << "\n\n Displaying Available Array:";
    for (int i = 0; i < m; i++)
    {
        cout << available[i] << " ";
    }

    // Step 1: Creating Need matix
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < m; j++)
        {
            need[i][j] = max[i][j] - alloc[i][j];
        }
    }

    cout << "\n\n Displaying Need Matrix:";
    display(need);

    // Step 2: Creating Flag variable to keep track of which process complete
    int flag[n];

    for (int i = 0; i < n; i++)
    {
        flag[i] = 0;
    }

    // Step 3: Allocating Resources if available is greater than need
    int safe_seq[n], ct = 0;
    int i, j, k, f;

    for (k = 0; k < n; k++)
    {
        for (i = 0; i < n; i++)
        {
            f = 0;
            if (flag[i] == 1)
            {
                continue;
            }

            for (j = 0; j < m; j++)
            {
                if (available[j] < need[i][j])
                {
                    f = 0;
                    break;
                }
                else
                {
                    f = 1;
                }
            }
            if (f == 1)
            {
                flag[i] = 1;
                break;
            }
        }

        if (i == n)
        {
            continue;
        }

        if (flag[i] == 1)
        {
            safe_seq[ct] = i;
            ct++;
            for (j = 0; j < m; j++)
            {
                available[j] += alloc[i][j];
            }
        }
    }
    f = 0;

    // Checking if Safe Sequence is present or not
    for (int i = 0; i < n; i++)
    {
        if (flag[i] == 0)
        {
            cout << "\n\n Safe Sequence Not Present!";
            f = 1;
            break;
        }
    }

    // Printing Safe Sequence
    if (f == 0)
    {
        cout << "\n\n Safe Seqence:";

        for (int i = 0; i < n; i++)
        {
            cout << "P" << safe_seq[i] + 1 << ",";
        }
    }

    return 0;
}
Output:
21 Program for Banker's Algorithm in Operating System

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