Visualizer for Sorting Algorithms

demo.mp4

Developed in C with SDL3. This small project allows you to visualize how different sorting algorithms work, like those youtube videos we all have seen. This is not the first one nor the best one, but this one is in C and that is something. Includes:

• Quick Sort
• Merge Sort
• Heap Sort
• Bubble Sort
• Insertion Sort
• Selection Sort
• Bogo Sort

The algorithms are implemented in src/algorithms.c and the visualizer is in src/main.c.

Usage

To compile and run the visualizer you will need to have SDL3 installed, as well as make and gcc installed. To compile, just run:

make
./main

Configuring

The visualizer can be configured in src/config.h. Options are:

• WIDTH and HEIGHT for the window size
• US_STEP between updates for the algorithms
• LIST_SIZE for the size of the list
• SPACING for the spacing between bars
• MIN_FREQ for the frequency of the lowest element
• MAX_FREQ for the frequency of the highest element

Once configured, the code must be compiled again with make.

Adding New Algorithms

Creating a New Algorithm

The new algorithm must be implemented in src/algorithms.c and declared in src/algorithms.h. The algorithms are executed in a separate thread, which has the advantage of us being able to reuse code from the algorithms directly. The only change needed is a call to the step(info, red_index, green_index1, green_index2, sound_index) every time we want the visualizer to show a change (be it a swap, a comparison...). Green can be used to indicate the compared elements, and red to show a pivot or similar. sound_index is the index of the element that should be played as a sound (bigger element, higher pitch).

Adding the algorithm to the code

Adding a new algorithm to the code is relatively simple. Steps to follow are:

1. Add the algorithm declaration to src/algorithms.h and the implementation to src/algorithms.c
2. Add the name of the algorithm to the State enum in src/main.c
3. In the switch statement in the function SDL_AppEvent add the key handler for the new algorithm:

    /* In main.c */
		switch (event->key.key) {
        /* ... */
		case SDLK_8:
			state = NEW_SORT;
			updateThread();
			break;
		case SDLK_ESCAPE:
        /* ... */
		}

4. In the function showMenu add the new algorithm to the types list.
5. Finally, in the function threadFunction add the new algorithm to the switch statement:

    /* In main.c */
	switch (state) {
        /* ... */
        case NEW_SORT:
            new_sort(&info);
            break;
        /* ... */
	}

Possible additions:

• Controls for speed and number of bars
• Add more algorithms
• Use SDL3_ttf??