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  1. #include <iostream>
  2. #include <string>
  3. #include <fstream>
  4. #include <limits>
  5.  
  6. void cat(std::string filename);
  7. void echo(std::string args);
  8. void cp(std::string source, std::string destination);
  9.  
  10. int main()
  11. {
  12.   std::string command = "", prompt = "$ ";
  13.   std::cout << std::endl << prompt;
  14.  
  15.   while (std::cin >> command)
  16.   {
  17.     if (command == "cat")
  18.     {
  19.       std::string source = "", arg = "";
  20.       std::cin >> source;
  21.  
  22.       if (std::getline(std::cin, arg) && arg.size() > 0)
  23.       {
  24.         std::cerr << "cat only accepts one argument" << std::endl << prompt;
  25.         continue;
  26.       }
  27.       else
  28.         std::cin.clear();
  29.  
  30.       cat(source);
  31.     }
  32.     else if (command == "echo")
  33.     {
  34.       std::string args;
  35.       while (std::cin.peek() == ' ')
  36.         std::cin.get();
  37.       std::getline(std::cin, args);
  38.  
  39.       echo(args);
  40.     }
  41.     else if (command == "cp")
  42.     {
  43.       std::string source = "", destination = "", arg = "";
  44.  
  45.       std::cin >> source >> destination;
  46.       if (std::getline(std::cin, arg) && arg.size() > 0)
  47.       {
  48.         std::cerr << "cp only accepts two arguments" << std::endl << prompt;
  49.         continue;
  50.       }
  51.       else
  52.         std::cin.clear();
  53.  
  54.       cp(source, destination);
  55.     }
  56.     else if (command == "PS1")
  57.     {
  58.       while (std::cin.peek() == ' ')
  59.         std::cin.get();
  60.  
  61.       std::getline(std::cin, prompt);
  62.     }
  63.     else if (command == "exit")
  64.     {
  65.       break;
  66.     }
  67.     else if (command == "ls")
  68.     {
  69.       system("ls");
  70.     }
  71.     else
  72.     {
  73.       std::cout << "Usage: " << std::endl
  74.                 << "cat [filename]" << std::endl
  75.                 << "\tDisplays file contents." << std::endl << std::endl
  76.                 << "echo [-n] [args ...]" << std::endl
  77.                 << "\tWrite arguments to the standard output." << std::endl << std::endl
  78.                 << "PS1 [prompt]" << std::endl
  79.                 << "\tChanges the prompt symbol(s)." << std::endl << std::endl
  80.                 << "cp [source] [destination]" << std::endl
  81.                 << "\tCopies the source file to the destination file." << std::endl << std::endl
  82.                 << "exit" << std::endl
  83.                 << "\tExits this prompt." << std::endl << std::endl;
  84.     }
  85.  
  86.     std::cout << prompt;
  87.   }
  88.  
  89.   return 0;
  90. }
  91.  
  92. void cat(std::string filename)
  93. {
  94.   std::ifstream file;
  95.   file.open(filename);
  96.   std::string line = "";
  97.   if (!file)
  98.   {    
  99.     std::cerr << "File open error" << std::endl;
  100.     return;
  101.   }
  102.  
  103.   while (std::getline(file, line))
  104.     std::cout << line << std::endl;
  105. }
  106.  
  107. void echo(std::string args)
  108. {
  109.   if (args.size() > 2 && args.substr(0, 3) == "-n ")
  110.   {
  111.     args = args.substr(3);
  112.     std::cout << args;
  113.   }
  114.   else if (args == "-n")
  115.     return;
  116.   else
  117.     std::cout << args << std::endl;
  118. }
  119.  
  120. void cp(std::string source, std::string destination)
  121. {
  122.   std::ifstream sourceFile;
  123.   std::ofstream destinationFile;
  124.   sourceFile.open(source);
  125.   destinationFile.open(destination);
  126.   std::string line = "";
  127.   while (std::getline(sourceFile, line))
  128.     destinationFile << line << std::endl;
  129. }
Success #stdin #stdout 0s 3044KB
comments (?)
stdin 
Standard input is empty
stdout 
$
https://ideone.com/6ISgo2
language:
C++14 (gcc 8.3)
created:
11 years ago
visibility:
public

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