cpp.tmd

---
title: Tmdoc - examples for the C++ programming language
author: Detlef Groth
date: 2025-09-14 16:11
include-before: |
    <style>
    body { max-width: 1000px; font-family: Candara, sans-serif; }
    pre  { font-family: Consolas; monospaced; }
    table { min-width: 400px; border-spacing: 5px;  border-collapse: collapse; }
    </style>
    <center>some links on top</center>
---

`tcl include header.md`

## Introduction

Below are some C++ coding examples.

## Hello World

```{.shell cmd="g++ %i -o cpp-hello&&./cpp-hello > %o" chunk.ext=cpp ext=txt}
#include <iostream>
int main() {
    std::cout << "Hello C++ World!" << std::endl;
    return(0);
}
```

## Image Creation

Here   an    example    which    does    create    an    image    using    the
[Cimg](https://cimg.eu) library. On a Linux Debian based system you should be able to install the library like this:

```
sudo apt install cimg-dev imagemagic 
```

The  imagemagick  tools are  required  to write for  instance  various  output
formats like png in the following example.


```
'``{.shell  cmd="g++ -O2 %i -o cimg&&./cimg -lX11 -lpthread -lm " chunk.ext=cpp ext=png include=false}
... code ..
'``
```

Output:

```{.shell  label=cimg cmd="g++ -O2 %i -o %b -lX11 -lpthread -lm &&./%b %o" chunk.ext=cpp ext=png include=false}
#include <CImg.h>
using namespace cimg_library;

int main(int argc, char **argv) {
    // Create a 300x200 RGB image, initialized to black
    CImg<unsigned char> img(300, 200, 1, 3, 0);

    // Define colors
    const unsigned char red[]   = {255, 0, 0};
    const unsigned char white[] = {255, 255, 255};

    // Draw a filled red rectangle (box) at (50,50) with size 200x100
    img.draw_rectangle(50, 50, 249, 149, red);

    // Draw "Hello World" in white, at position (90, 90)
    img.draw_text(90, 90, "Hello World", white);

    // Display the image in a window
    //img.display("Hello World Example");

    // Optionally, save the image to a file
    img.save(argv[1]);

    return 0;
}
```

![](cimg.png)