Create bankers_algorithm.cpp

cpu_scheduling_algorithms/bankers_algorithm.cpp

@@ -0,0 +1,146 @@
+#include <iostream>
+#include <vector>
+#include <cassert>
+#include <ctime>
+#include <cstdlib>
+
+using namespace std;
+
+const int P = 5;
+const int R = 3;
+
+/**
+ * BankersAlgorithm class represents the Banker's Algorithm for resource allocation.
+ * It checks if a system is in a safe state and computes a safe sequence.
+ */
+class BankersAlgorithm {
+public:
+    /**
+     * Constructor for BankersAlgorithm class.
+     *
+     * @param processes An array of process IDs.
+     * @param avail An array representing the available resources.
+     * @param maxm A 2D array representing the maximum resources for each process.
+     * @param allot A 2D array representing the resources currently allocated to each process.
+     * @param num_processes The number of processes.
+     * @param num_resources The number of resource types.
+     */
+    BankersAlgorithm(int processes[], int avail[], int maxm[][R], int allot[][R], int num_processes, int num_resources)
+        : num_processes_(num_processes), num_resources_(num_resources) {
+        
+        for (int i = 0; i < num_processes_; i++) {
+            processes_.push_back(processes[i]);
+        }
+        
+        for (int i = 0; i < num_resources_; i++) {
+            avail_.push_back(avail[i]);
+        }
+        
+        for (int i = 0; i < num_processes_; i++) {
+            vector<int> max_row;
+            vector<int> allot_row;
+            vector<int> need_row;
+            
+            for (int j = 0; j < num_resources_; j++) {
+                max_row.push_back(maxm[i][j]);
+                allot_row.push_back(allot[i][j]);
+                need_row.push_back(maxm[i][j] - allot[i][j]);
+            }
+            
+            max_.push_back(max_row);
+            allot_.push_back(allot_row);
+            need_.push_back(need_row);
+        }
+        
+        safe_sequence_.resize(num_processes_);
+        work_ = avail_;
+    }
+
+    /**
+     * Check if the system is in a safe state.
+     *
+     * @return True if the system is in a safe state, otherwise false.
+     */
+    bool is_safe() {
+        vector<bool> finish(num_processes_, false);
+        int count = 0;
+
+        while (count < num_processes_) {
+            bool found = false;
+            for (int i = 0; i < num_processes_; i++) {
+                if (!finish[i]) {
+                    bool can_allocate = true;
+                    for (int j = 0; j < num_resources_; j++) {
+                        if (need_[i][j] > work_[j]) {
+                            can_allocate = false;
+                            break;
+                        }
+                    }
+                    if (can_allocate) {
+                        for (int j = 0; j < num_resources_; j++) {
+                            work_[j] += allot_[i][j];
+                        }
+                        safe_sequence_[count++] = i;
+                        finish[i] = true;
+                        found = true;
+                    }
+                }
+            }
+            if (!found) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * Print the safe sequence of processes.
+     */
+    void print_safe_sequence() {
+        cout << "System is in a safe state. Safe sequence is: ";
+        for (int i = 0; i < num_processes_ - 1; i++) {
+            cout << "P" << processes_[safe_sequence_[i]] << " -> ";
+        }
+        cout << "P" << processes_[safe_sequence_[num_processes_ - 1]] << endl;
+    }
+
+private:
+    int num_processes_;
+    int num_resources_;
+    vector<int> processes_;
+    vector<int> avail_;
+    vector<vector<int>> max_;
+    vector<vector<int>> allot_;
+    vector<vector<int>> need_;
+    vector<int> safe_sequence_;
+    vector<int> work_;
+};
+
+/**
+ * Test the Banker's Algorithm with predefined test cases.
+ * This function checks if the algorithm behaves correctly.
+ */
+void test_algorithm() {
+    // Test Case 1
+    int processes1[] = {0, 1, 2, 3, 4};
+    int avail1[] = {3, 3, 2};
+    int maxm1[][R] = {{7, 5, 3}, {3, 2, 2}, {9, 0, 2}, {2, 2, 2}, {4, 3, 3}};
+    int allot1[][R] = {{0, 1, 0}, {2, 0, 0}, {3, 0, 2}, {2, 1, 1}, {0, 0, 2}};
+
+    BankersAlgorithm banker1(processes1, avail1, maxm1, allot1, 5, 3);
+    assert(banker1.is_safe() == true);
+
+    // Test Case 2
+    int processes2[] = {0, 1, 2};
+    int avail2[] = {1, 2, 2};
+    int maxm2[][R] = {{2, 2, 2}, {3, 2, 2}, {2, 2, 2}};
+    int allot2[][R] = {{1, 0, 1}, {2, 1, 0}, {1, 2, 2}};
+
+    BankersAlgorithm banker2(processes2, avail2, maxm2, allot2, 3, 3);
+    assert(banker2.is_safe() == false);
+}
+
+int main() {
+    test_algorithm();
+    return 0;
+}