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  1. // Attached: HW_11
  2. // File: HW_11
  3. // Programmer: Elaine Torrez
  4. // Class: CMPR 121
  5.  
  6. #include <iostream>
  7. #include <fstream>
  8. #include <cmath>
  9. #include <ctime>
  10. #include <thread>
  11. using namespace std;
  12.  
  13. void writeRoots();
  14. void writeSquares();
  15.  
  16. int main()
  17. {
  18.     clock_t start;
  19.     clock_t end;
  20.     double runtimeWithoutThreads;
  21.     double runtimeWithThreads;
  22.  
  23.     cout << "main: startup\n\n";
  24.  
  25.     start = clock();
  26.  
  27.     cout << "Waiting for file thread\n";
  28.     writeRoots();
  29.     writeSquares();
  30.  
  31.     end = clock();
  32.  
  33.     runtimeWithoutThreads = static_cast<double>(end - start) / CLOCKS_PER_SEC;
  34.  
  35.     cout << "\nmain: done\n";
  36.     cout << "Runtime without threads = " << runtimeWithoutThreads << " seconds.\n\n";
  37.  
  38.     start = clock();
  39.  
  40.     cout << "main: startup\n\n";
  41.     cout << "Waiting for file thread\n";
  42.  
  43.     thread firstThread(writeRoots);
  44.     thread secondThread(writeSquares);
  45.  
  46.     firstThread.join();
  47.     secondThread.join();
  48.  
  49.     end = clock();
  50.  
  51.     runtimeWithThreads = static_cast<double>(end - start) / CLOCKS_PER_SEC;
  52.  
  53.     cout << "\nmain: done\n";
  54.     cout << "Runtime with threads = " << runtimeWithThreads << " seconds.\n\n";
  55.  
  56.     if (runtimeWithThreads < runtimeWithoutThreads)
  57.     {
  58.         cout << "The multithreaded version saved time.\n";
  59.     }
  60.     else
  61.     {
  62.         cout << "The multithreaded version did not save time.\n";
  63.     }
  64.  
  65.     return 0;
  66. }
  67.  
  68. void writeRoots()
  69. {
  70.     ofstream outputFile;
  71.     int number;
  72.  
  73.     outputFile.open("roots.txt");
  74.  
  75.     cout << "Writing 1,000,000 square roots to a file\n";
  76.  
  77.     for (number = 1; number <= 1000000; number++)
  78.     {
  79.         outputFile << "The square root of " << number << " is "
  80.                    << sqrt(number) << endl;
  81.     }
  82.  
  83.     outputFile.close();
  84.  
  85.     cout << "The square roots are ready.\n";
  86. }
  87.  
  88. void writeSquares()
  89. {
  90.     ofstream outputFile;
  91.     int number;
  92.     long long square;
  93.  
  94.     outputFile.open("squares.txt");
  95.  
  96.     cout << "Squaring 1000000 numbers\n";
  97.  
  98.     for (number = 1; number <= 1000000; number++)
  99.     {
  100.         square = static_cast<long long>(number) * number;
  101.  
  102.         outputFile << number << " squared is " << square << endl;
  103.     }
  104.  
  105.     outputFile.close();
  106.  
  107.     cout << "The squares are ready.\n";
  108. }
Success #stdin #stdout 0.26s 5316KB
comments (?)
stdin 
Standard input is empty
stdout 
main: startup

Waiting for file thread
Writing 1,000,000 square roots to a file
The square roots are ready.
Squaring 1000000 numbers
The squares are ready.

main: done
Runtime without threads = 0.109116 seconds.

main: startup

Waiting for file thread
Squaring 1000000 numbers
Writing 1,000,000 square roots to a file
The squares are ready.
The square roots are ready.

main: done
Runtime with threads = 0.146913 seconds.

The multithreaded version did not save time.
https://ideone.com/q0Nh0j
language:
C++ (gcc 8.3)
created:
1 day ago
visibility:
public

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