philip82148's blog

A C++ Debugging Library that Can Print Vectors, Maps, Sets, Tuples, and All
By philip82148, history, 3 months ago, In English

Hi Codeforces! I'm a Japanese graduate student, and I've been programming as a hobby since I was 11. I started CP last year, and since then, I've been working on a C++ debugging library that can print variables of almost any type, like vectors, maps, tuples, and more. In this blog, I want to share it with you. Link: https://github.com/philip82148/cpp-dump

Feature Summary

A Wide Variety of Supported Types Section
Example Code
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Auto Indent Section
Example Code
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Customizable Output Color Section
Example Code
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20+ Manipulators to Change the Display Style Section
Example Code
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  • The string representation of variables is similar to JavaScript, Python, and C++ syntax. The output is readable without being overloaded with information. (You can add more details using manipulators if you want.)
  • The filename, line number, and function name can be included in the output.
  • By using macros, cpp-dump supports user-defined types as well. There is no need to write new functions for printing.

See the Features section of the README for details.

Simple Usage

Pass variables to the cpp_dump() macro. For more detailed usage, please see README of the repo.
Full Example Code

#include <bits/stdc++.h>
#include "path/to/cpp-dump/cpp-dump.hpp"
using namespace std;

int main() {
  vector<vector<int>> my_vector{{3, 5, 8, 9, 7}, {9, 3, 2, 3, 8}};
  cpp_dump(my_vector);
}

Let's try it!

  1. Clone the repo(git clone https://github.com/philip82148/cpp-dump) or download it (zip) (tar.gz) from Releases.
  2. Compile & run the code below to test the library
#include <bitset>
#include <complex>
#include <iostream>
#include <map>
#include <optional>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <utility>
#include <variant>
#include <vector>

#include "path/to/cpp-dump/cpp-dump.hpp"
namespace cp = cpp_dump;
using namespace std;

int main() {
  bool my_bool = true;
  double my_double = 3.141592;
  int my_int = 65;
  char my_char = 'a', LF_char = '\n';
  string my_string = "This is a string.";
  int *int_ptr = &my_int;
  void *void_ptr = &my_int;
  vector<vector<int>> my_vector{{3, 5, 8, 9, 7}, {9, 3, 2, 3, 8}};
  set<char> my_set{'A', 'p', 'p', 'l', 'e'};
  map<int, int> my_map{{2, 6}, {4, 6}, {5, 3}};
  multiset<char> my_multiset{'A', 'p', 'p', 'l', 'e'};
  multimap<int, int> my_multimap{{2, 4}, {4, 6}, {5, 3}, {4, 7}};
  pair<int, char> my_pair{8, 'a'};
  tuple<int, double, string> my_tuple{7, 4.5, "This is a string."};
  queue<int> my_queue;
  priority_queue<int> my_priority_queue;
  stack<int> my_stack;
  for (auto v : {1, 2, 3, 4, 5}) my_queue.push(v), my_priority_queue.push(v), my_stack.push(v);
  bitset<8> my_bitset(0x3a);
  complex<double> my_complex{1.0, -1.0};
  optional<int> my_optional{15};
  variant<int, string> my_variant{"This is a string."};
  vector<pair<int, string>> vector_of_pairs{{1, "apple"}, {3, "banana"}};

  CPP_DUMP_SET_OPTION(max_line_width, 100);
  CPP_DUMP_SET_OPTION(max_iteration_count, 10);

  clog << "\n// Basic Type" << endl;
  cpp_dump(my_bool, my_double, my_int), cpp_dump(my_string, my_char, LF_char);
  cpp_dump(int_ptr, void_ptr, nullptr);

  clog << "\n// Container" << endl;
  cpp_dump(my_vector);

  clog << "\n// Set/Map" << endl;
  cpp_dump(my_set), cpp_dump(my_map);

  clog << "\n// Multiset/Multimap" << endl;
  cpp_dump(my_multiset), cpp_dump(my_multimap);

  clog << "\n// Tuple" << endl;
  cpp_dump(my_tuple), cpp_dump(my_pair);

  clog << "\n// FIFO/LIFO" << endl;
  cpp_dump(my_queue), cpp_dump(my_priority_queue), cpp_dump(my_stack);

  clog << "\n// Other" << endl;
  cpp_dump(my_bitset), cpp_dump(my_complex);
  cpp_dump(my_optional, nullopt), cpp_dump(my_variant);

  clog << "\n// Combination" << endl;
  cpp_dump(vector_of_pairs);

  vector<vector<int>> some_huge_vector(100, vector<int>(100));
  vector<vector<unsigned int>> unsigned_int_vector(100, vector<unsigned int>(100));

  for (int i = 0; i < 100; ++i) {
    for (int j = 0; j < 100; ++j) {
      some_huge_vector[i][j] = ((i + 1) * 7 % 19 - 9) * ((j + 1) * 3 % 19 - 9);
      unsigned_int_vector[i][j] = abs(some_huge_vector[i][j]);
    }
  }

  clog << "\n// Manipulator Test" << endl;
  cpp_dump(some_huge_vector | cp::back() | cp::both_ends() | cp::dec(2));
  cpp_dump(some_huge_vector | cp::dec(2) | cp::index());
}

There are other installation methods, too. Please see the Installation section of the README for details.

Recommended usage in competitive programming

cpp_dump(vars...) is long, so let's shorten it to dump(vars...) by macro. For details, see For Competitive Programming Use section of the README.

#ifndef ONLINE_JUDGE
#include "path/to/cpp-dump/cpp-dump.hpp"
#define dump(...) cpp_dump(__VA_ARGS__)
#else
#define dump(...)
#endif

News

v0.7.0 released on August 19 has lots of new features.
If you're using an older version, please update it! (For git users, run git pull)

Conclusion

I hope this library helps!
Also, if you could upvote this blog and give a star to the repo, I would really appreciate it.

  • Vote: I like it
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  • Vote: I do not like it

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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

This looks interesting! I'll definitely try it out!

I used to debug code with the following snippet, which I learned in a competitive programming course. It allows you to print any type of variable and pass multiple arguments to the debug() function. It's been really helpful for debugging.

Snippet
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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

But can it print my profile picture?

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    3 months ago, # ^ |
      Vote: I like it +27 Vote: I do not like it
    Just need to add this function
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3 months ago, # |
← Rev. 2   Vote: I like it +5 Vote: I do not like it

Is it possible to support custom class/structure? (just like print/disp in gdb do)

Edit: I see this can be achieved by using some macros or operator, but it would be more convenient if a default result can be provided (maybe diffcult to implement in c++)

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3 months ago, # |
← Rev. 5   Vote: I like it 0 Vote: I do not like it

If you want to customize the string representation of a custom class more flexibly, you can do it as follows.

Code

For reference, you can support AtCoder Library's modint by calling the function recursively like this.

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3 months ago, # |
  Vote: I like it +1 Vote: I do not like it

How do I turn off the color output?

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    3 months ago, # ^ |
    ← Rev. 2   Vote: I like it 0 Vote: I do not like it

    Pls see the end of the Customizable output color section.

    CPP_DUMP_SET_OPTION(es_style, cp::types::es_style_t::no_es);
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      3 months ago, # ^ |
      ← Rev. 7   Vote: I like it 0 Vote: I do not like it

      Why does it display the message as an error in cp editor? Screenshot-20241004-192827

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        3 months ago, # ^ |
          Vote: I like it 0 Vote: I do not like it

        cpp_dump() outputs to the standard error output (std::clog) by default. So, for example, if you want to change the output destination to the standard output (std::cout), you can do it as follows.

        Code
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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Here is a list of all the supported types: Supported types
Since cpp_dump() prints variables recursively, it can print any combination of nested containers from the list.

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3 months ago, # |
  Vote: I like it +1 Vote: I do not like it

Hi. I found your library really helpful.

Just wanted your help on this thing :

The dump function is working perfectly fine when the output is shown on terminal. But when I am using the CPH Judge VS Code extension, the output being displayed is something like this : 

[codeforces.cpp:85] v => [ 1, 2, 3, 4, 5 ]

I know you might not be aware of the CPH extension, but any suggestion from your side would be of great help.

Thanks.

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    3 months ago, # ^ |
    ← Rev. 2   Vote: I like it +3 Vote: I do not like it

    I use cp editor but have encountered the same problem.

    1) Disable the display of colored text using this code:

    This code

    2) cpp_dump() outputs to the standard error output (std::clog) by default. So, for example, if you want to change the output destination to the standard output (std::cout), you can do it as follows.

    This code
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      3 months ago, # ^ |
        Vote: I like it +3 Vote: I do not like it

      this is the full code I'm using

      code
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        3 months ago, # ^ |
          Vote: I like it 0 Vote: I do not like it

        Yeah, the output is now being formatted perfectly.

        Thanks a lot!

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    3 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    For reference, the garbled character is '\x1b' (a char with a hex value of 0x1b), which is called an escape sequence and controls color.
    Running this in the terminal helps you understand this.

    Command

    Somehow I couldn't use cpeditor in my environment, so I didn't test, but probablly cpeditor doesn't recognize escape sequences.

    This is advanced knowledge, but a terminal is treated as a file in macOS or Linux.
    You can get the path of a terminal by the tty command.

    Command
    (Command to help you understand this)

    So, you can write the output of cpp_dump() to the terminal while using cpeditor like this.

    Code

    By doing this, you can still get colored output while using cpeditor.

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      3 months ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      I did it now, and cpp_dump() doesn't output anything.

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        3 months ago, # ^ |
          Vote: I like it 0 Vote: I do not like it

        Did you change /dev/pts/7 to your own terminal's path?
        The file path is the result of the tty command.

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          3 months ago, # ^ |
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          Yeah, I did it.

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            3 months ago, # ^ |
            ← Rev. 2   Vote: I like it 0 Vote: I do not like it

            Does this command work? It should produce the output 'ABC' in the terminal.

            Command
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              3 months ago, # ^ |
                Vote: I like it 0 Vote: I do not like it

              Sorry, I just realized what you want to do. My knowledge of linux is not that strong. So I thought this command would output the data in the cp editor itself.

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3 months ago, # |
  Vote: I like it +1 Vote: I do not like it

I use vim and this is best debugger i have ever seen for cp even better than mine

Thanks.

my debugger

my debugger cant give colored output and the structured way.

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3 months ago, # |
  Vote: I like it +1 Vote: I do not like it

This is really useful! Especially since it's a header-only library. I added it as a git submodule to my project.

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3 months ago, # |
  Vote: I like it +1 Vote: I do not like it

Great work! Upvoted and starred.

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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

If you want to configure the library outside of the main function, you can use the CPP_DUMP_SET_OPTION_GLOBAL() macro.

Code

And here is the list of all available options: Configuration options

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2 months ago, # |
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I switched to Windows and now it doesn't work, maybe I need to download another code just I don't understand it

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    2 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    It's tested on Windows too. It requires C++17 or higher. Are you using the correct version? If you are, could you provide the error message?

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      2 months ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      command: g++ -std=c++17 main.cpp

      error
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        2 months ago, # ^ |
          Vote: I like it 0 Vote: I do not like it

        Could you tell me the result of this command?

        Command
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