The Matrix: Char Reloaded

Question

amrith92 119 Junior Poster

18 Years Ago

Here's a funny program that simulates the matrix...waaay off topic...

#include <iostream>
#include <ctime>

using namespace std;

const int NotUsed=system("color 02");

int main()
{
    clock();
    int n;
    double time;
    char matrixwords[]="  aijk FGHIJKlmnopqrs  ABCDtuvELMNO  PQRS bcde fghTUVWXYwxyzZ";
    char matrix[]="01001100100101011110";
    
    clock();
    for(int o=1; o<=70; o++)
    {
            cout << "/";
            }
            cout << "\n\n\t\t\tThe Matrix\n\n";
    for(int o=1; o<=70; o++)
    {
            cout << "/";
            }
            cout << "\n\n\tEnter Matrix ID: (KB's of Data) ::==:: ";
            cin >> n;
            for(double t=-1000; t<=1000000; t++);
            cout << "\n\n\tLoading Matrix Engine.";
            for(double t=0; t<=5; t++)
            {
                       for(double u=-10000; u<=10000000; u++);
                       cout << " . ";
                       }
                       time=clock()/1000.0;
                       cout << "\n\n\t\tYou waited " << time << " seconds for the matrix to generate\n\n\t";
    
    for(int i=1; i<=n; i++)
    {
            for(int j=1; j<=60; j++)
            {
                    if((j%2==0) || (j%5==0) || (j%13==0))
                    {
                              int ran( rand()%21 );
                              cout << matrix[ran];
                              }
                              else if(j%3==0)
                              {
                                   int ran( rand()%66 );
                                  cout << matrixwords[ran];
                                  }
                                  else if(j%7==0)
                                  {
                                       int ran( rand()%66 );
                                       cout << matrixwords[ran];
                                       }
                                  else
                                  {
                                      int ran( rand()%66 );
                                      cout << matrixwords[ran];
                                      }
                    }
                    cout << "\n\t";
            }
            time+=clock()/1000.0;
    
    cout << "\n\n\tTotal Time Taken for the Matrix to Run: " << time << " s\n\n\t";
    cin.get();
    return 0;
}

programmed in c++.. kinda dumb..but still

c++

5 Contributors
11 Replies
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Latest Post 18 Years Ago Latest Post by amrith92

Dani AI

Generated 6 Months Ago

Nice little toy from and fun reactions from , and others. A few practical notes that turn this demo into a safer, more portable snippet and explain the common pitfalls people hit when they copy-and-run "Matrix" demos.

Avoid side effects during static initialization (calling system(...) in a global initializer). Do setup in main so startup ordering and errors are clearer.
Don’t busy-wait for timing (for loops that just increment a double). Use std::this_thread::sleep_for for delays and std::chrono::steady_clock for timing.
Prefer <random> (std::mt19937 + uniform_int_distribution) over rand() and avoid using % with an incorrectly computed modulus — off-by-one or zero-length strings cause undefined behavior.
Buffer each line into a std::string and write it once (lots faster than calling operator<< per character). For color/clear, use ANSI escapes or a proper console library rather than system("cls")/system("clear").

Example (modern C++11+) — compact, safer matrix effect:

#include <iostream>
#include <random>
#include <string>
#include <chrono>
#include <thread>

int main() {
    const std::string chars = "  aijkFGHIJKlmnopqrs  ABCDtuvELMNO  PQRS bcde fghTUVWXYwxyzZ01";
    std::random_device rd;
    std::mt19937 gen(rd());
    std::uniform_int_distribution<std::size_t> dist(0, chars.size() - 1);

    for (int line = 0; line < 200; ++line) {
        std::string out;
        out.reserve(60);
        for (int col = 0; col < 60; ++col) out.push_back(chars[dist(gen)]);
        std::cout << out << '\n';
        std::this_thread::sleep_for(std::chrono::milliseconds(40));
    }
}

Troubleshooting: if the program appears to generate the same output each run, check the seed (random_device may be deterministic on some platforms); if it crashes, verify the character buffer length before building the distribution; if colors do not show, enable ANSI processing on Windows or use a cross-platform terminal library. This keeps the effect visually similar to the original while removing undefined behavior, improving timing accuracy, and making the code easier to maintain.

All 11 Replies

ArkM 1,090 Postaholic

18 Years Ago

Yes, it's a severe blow for all C++-lovers...
And your question is...

Tigran 14 Junior Poster in Training

18 Years Ago

Compiled id, kindda funny ya, though...
Not really usefull to be honest :P

ArkM 1,090 Postaholic

18 Years Ago

Well, in that case a free advice for a C++ coder: look at the C++ language definition. Must be int main() , not improbable void main() in signature ;)...

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amrith92 119 Junior Poster · Answer 1 · 2008-09-07T17:42:28+00:00

Yes, it's a severe blow for all C++-lovers...
And your question is...

No question...I just thought it was kinda funny...it was in another forum, but got moved here...

Compiled id, kindda funny ya, though...
Not really usefull to be honest :P

Yeah...there is no point in the code...it just simulates the matrix

Member #46692 · Answer 2 · 2008-09-07T20:24:41+00:00

Whatever it is, it looks pretty lame and probably could be improved with a clearscreen function that is system dependent.

amrith92 119 Junior Poster · Answer 3 · 2008-09-07T23:04:15+00:00

Well, in that case a free advice for a C++ coder: look at the C++ language definition. Must be int main() , not improbable void main() in signature ;)...

Yeah...I know about that but int main() would need a return statement, which would make my signature 6 lines, one more than is allowed... and anyway, its only just a signature!

Duoas 1,025 Postaholic Featured Poster · Answer 4 · 2008-09-07T23:18:49+00:00

Reminds me of the grandaddy of all screensavers. Something like

#include <stdlib.h>
#include <stdio.h>
#include <time.h>

int main()
  {
  srand( time( NULL ) );
  while (1) printf( "%*c", rand() % 15, '*' );
  return 0;
  }

(This, of course, is just the simplest possible version...)

ArkM 1,090 Postaholic · Answer 5 · 2008-09-07T23:42:57+00:00

Thank you, Duodas, for this brilliant code!
It's so pity it's not a part of the C RTL...

amrith92 119 Junior Poster · Answer 6 · 2008-09-07T23:55:50+00:00

amrith92 119 Junior Poster

18 Years Ago

You gotta admit, the Classics are good!

ArkM 1,090 Postaholic · Answer 7 · 2008-09-08T00:45:58+00:00

Yeah...I know about that but int main() would need a return statement, which would make my signature 6 lines, one more than is allowed... and anyway, its only just a signature!

Good news for amrith92: The C++ Standard does not require explicit return statement in int main() !

amrith92 119 Junior Poster · Answer 8 · 2008-09-08T01:04:45+00:00

Good news for amrith92: The C++ Standard does not require explicit return statement in int main() !

Hear, Hear! So this means my Signature is valid!! Anyways, it isn't a standard and I would urge myself never to comment on it again!

The Matrix: Char Reloaded

Dani AI

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