A generic stack accepts any data type the user wants his/her input to be in. It helps the user use a single stack class to create multiple stacks with varying input datatypes.
This project uses the Java Random class to generate a captcha string of length 6 characters. The GUI is made using Java Swing and awt packages.
It consists of a 9x9 textbox grid. The value for a textbox is set if it adheres to the rules of sudoku, otherwise, the code backtracks and checks for other possible values.