C++ online IDE & code editor for technical interviews

Guidelines to use C++ in this online IDE

We run your C++ code with GCC 8. You should define an int main() entrypoint. The gcc compiler is invoked with the following args:

g++ -Wall -fsanitize=address -std=c++17 -pthread \
-lboost_date_time -lboost_regex -lboost_system -lboost_thread -lboost_timer -lboost_filesystem \
-lssl -lcrypto -lmysqlcppconn

Which results in:

• Use the C++17 standard
• Turn on all warning messages
• Compile in debug mode
• Warn on memory use-after-free bugs and other memory issues with ASan. If you see an unusual message or segfault, it’s likely ASan picking up a use-after-free or use of uninitialized memory bug in your code.
• Link the pthread library
• Link a few static boost libraries

We also provide a few libraries:

• Boost is provided, with most of its header-only libraries working straight out of the box. Of its statically compiled components, we link to DateTime, Regex, System, Thread, and Timer. If you need more than those, please let us know!
• nlohmann/json, a convenient and simple JSON library. To use it on CoderPad, just include "json.hpp" and go nuts:

  #include "json.hpp"
  #include <iostream>

  int main() {
    nlohmann::json j2 = {
      {"hello", "world"}
    };
    std::cout << j2;
  }

Code language: CSS (css)

• Catch, a C++ testing library. Catch is a single-header library and very easy to get started with. To use it on CoderPad, simply define a macro and include the header like so:

  #define CATCH_CONFIG_MAIN
  #include "catch.hpp"

  unsigned int Factorial( unsigned int number ) {
      return number <= 1 ? 1 : Factorial(number - 1) * number;
  }

  TEST_CASE( "Factorials are computed", "[factorial]" ) {
      REQUIRE( Factorial(0) == 1 );
      REQUIRE( Factorial(1) == 1 );
      REQUIRE( Factorial(2) == 2 );
      REQUIRE( Factorial(3) == 6 );
      REQUIRE( Factorial(10) == 3628800 );
  }
Code language: C++ (cpp)

If you do so, you should NOT define your own main method. You can also read more about Catch’s macros for testing.

• Eigen, a library for linear algebra. We provide all of the Eigen modules and header files to the environment. To use it in CoderPad, just include the header that you want and instantiate an object:

  #include <iostream>
  #include <Eigen/Dense>

  using Eigen::MatrixXd;

  int main()
  {
    MatrixXd m(2,2);
    m(0,0) = 3;
    m(1,0) = 2.5;
    m(0,1) = -1;
    m(1,1) = m(1,0) + m(0,1);
    std::cout << m << std::endl;
  }Code language: C++ (cpp)