These are just a few old C++ projects from undergrad.

FourierTransform2D implements a 2D DFT and inverse DFT.

Icosahedron generates a 3D rendering of an icosahedron.

MBSet is a GUI for rendering the Mandelbrot set with a zoom feature.

RSA is a C++ implementation of the RSA algorithm.

ThreadsTransform2D is a multi-threaded version of FourierTransform2D.

Vector is just a from-scratch implementation of the basic features of std::vector.