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  1. #include <iostream>
  2. #include <thread>
  3. #include <chrono>
  4. #include <atomic>
  5. #include <mutex>
  6.  
  7. using namespace std;
  8.  
  9. // Shared flags to indicate process readiness (simulating atomic behavior)
  10. atomic<bool> flag0(false);  // Atomic flag for process 0
  11. atomic<bool> flag1(false);  // Atomic flag for process 1
  12. mutex mtx;  // Mutex for safe access to shared variables
  13.  
  14. void process(int id) {
  15.     int other = 1 - id;  // Determine the other process
  16.  
  17.     for (int i = 0; i < 3; ++i) {  // Each process executes 3 times
  18.         {
  19.             // Lock the mutex to ensure safe access to shared variables
  20.             lock_guard<mutex> lock(mtx);
  21.             if (id == 0) {
  22.                 flag0 = true;  // Set the flag for process 0
  23.             } else {
  24.                 flag1 = true;  // Set the flag for process 1
  25.             }
  26.  
  27.             // Busy-wait while the other process is active
  28.             while ((id == 0 && flag1) || (id == 1 && flag0)) {
  29.                 // Do nothing, just wait
  30.             }
  31.  
  32.             // Critical section
  33.             cout << "Process " << id << " is in critical section" << endl;
  34.             this_thread::sleep_for(chrono::seconds(1));  // Simulating critical section delay
  35.  
  36.             if (id == 0) {
  37.                 flag0 = false;  // Reset flag after critical section
  38.             } else {
  39.                 flag1 = false;  // Reset flag after critical section
  40.             }
  41.         }
  42.  
  43.         // Remainder section
  44.         cout << "Process " << id << " is in remainder section" << endl;
  45.         this_thread::sleep_for(chrono::milliseconds(500));  // Simulating remainder section delay
  46.     }
  47. }
  48.  
  49. int main() {
  50.     // Creating two threads (simulating two processes)
  51.     thread t1(process, 0);
  52.     thread t2(process, 1);
  53.  
  54.     // Start both threads
  55.     t1.join();  // Wait for thread t1 to finish
  56.     t2.join();  // Wait for thread t2 to finish
  57.  
  58.     return 0;
  59. }
Success #stdin #stdout 0.01s 5260KB
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stdin
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Standard input is empty
stdout
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Process 1 is in critical section
Process 1 is in remainder section
Process 0 is in critical section
Process 0 is in remainder section
Process 1 is in critical section
Process 1 is in remainder section
Process 0 is in critical section
Process 0 is in remainder section
Process 1 is in critical section
Process 1 is in remainder section
Process 0 is in critical section
Process 0 is in remainder section
https://ideone.com/Vv41mD
language:
C++ (gcc 8.3)
created:
12 days ago
visibility:
public

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