For example, we convert a decimal number into a hexadecimal number, divide it by sixteen with one of the most common algorithms, and set the remainder as a function. Then reverse all the remainder to another function.
If it is still displayed, it is necessary to set up a display function, which can display each bit of hexadecimal with switch multi-branch selection statement.
Only the methods are mentioned here, and the specific procedures still depend on your own reading and writing.