banker.cpp

#include <iostream>
#include <fstream>
#include <vector>
using namespace std;

int main()
{
    string filename = "input.txt";
    ifstream in(filename);

    if (!in)
    {
        cerr << "Error: could not open file " << filename << endl;
        return 1;
    }

    int nProc, nRes;
    in >> nProc >> nRes;

    vector<vector<int>> allocation(nProc, vector<int>(nRes));
    vector<vector<int>> maxm(nProc, vector<int>(nRes));
    vector<int> available(nRes);

    // Read Allocation matrix
    for (int i = 0; i < nProc; ++i)
    {
        for (int j = 0; j < nRes; ++j)
        {
            in >> allocation[i][j];
        }
    }

    // Read Max matrix
    for (int i = 0; i < nProc; ++i)
    {
        for (int j = 0; j < nRes; ++j)
        {
            in >> maxm[i][j];
        }
    }

    // Read Available vector
    for (int j = 0; j < nRes; ++j)
    {
        in >> available[j];
    }

    in.close();

    // Compute Need matrix: Need = Max - Allocation
    vector<vector<int>> need(nProc, vector<int>(nRes));

    for (int i = 0; i < nProc; ++i)
    {
        for (int j = 0; j < nRes; ++j)
        {
            need[i][j] = maxm[i][j] - allocation[i][j];
        }
    }

    cout << "==============================\n";
    cout << "   Banker's Algorithm Check   \n";
    cout << "==============================\n\n";

    cout << "Number of processes: " << nProc << endl;
    cout << "Number of resource types: " << nRes << endl;

    cout << "\nAllocation matrix:\n";
    for (int i = 0; i < nProc; ++i)
    {
        for (int j = 0; j < nRes; ++j)
        {
            cout << allocation[i][j] << " ";
        }
        cout << endl;
    }

    cout << "\nMax matrix:\n";
    for (int i = 0; i < nProc; ++i)
    {
        for (int j = 0; j < nRes; ++j)
        {
            cout << maxm[i][j] << " ";
        }
        cout << endl;
    }

    cout << "\nAvailable vector:\n";
    for (int j = 0; j < nRes; ++j)
    {
        cout << available[j] << " ";
    }
    cout << endl;

    cout << "\nNeed matrix (Max - Allocation):\n";
    for (int i = 0; i < nProc; ++i)
    {
        for (int j = 0; j < nRes; ++j)
        {
            cout << need[i][j] << " ";
        }
        cout << endl;
    }

    // Banker's safety algorithm
    vector<int> work = available;
    vector<bool> finish(nProc, false);
    vector<int> safeSequence;

    int finishedCount = 0;

    while (finishedCount < nProc)
    {
        bool foundProcess = false;

        for (int i = 0; i < nProc; ++i)
        {
            if (!finish[i])
            {
                bool canFinish = true;

                for (int j = 0; j < nRes; ++j)
                {
                    if (need[i][j] > work[j])
                    {
                        canFinish = false;
                        break;
                    }
                }

                if (canFinish)
                {
                    for (int j = 0; j < nRes; ++j)
                    {
                        work[j] += allocation[i][j];
                    }

                    finish[i] = true;
                    safeSequence.push_back(i);
                    finishedCount++;
                    foundProcess = true;

                    break;
                }
            }
        }

        if (!foundProcess)
        {
            break;
        }
    }

    bool allFinished = true;
    for (int i = 0; i < nProc; ++i)
    {
        if (!finish[i])
        {
            allFinished = false;
            break;
        }
    }

    cout << "\n------------------------------\n";
    if (allFinished)
    {
        cout << "System is in a SAFE state.\n";
        cout << "Safe sequence: ";
        for (int k = 0; k < (int)safeSequence.size(); ++k)
        {
            cout << "P" << safeSequence[k];
            if (k != (int)safeSequence.size() - 1)
            {
                cout << " -> ";
            }
        }
        cout << endl;
    }
    else
    {
        cout << "System is NOT in a safe state.\n";
    }
    cout << "------------------------------\n";

    return 0;
}