Different functions with one Arduino Uno

Hello!
Is it possible to have about 3 different codes in one Arduino Uno board? I have 3 different functions for my Arduino project, and every function have different sensors but one led or a lamp. And is it possible to have switches to switch the functions and choose one of them or smth.

You can certainly write a program that contains a number of different functions and the different functions can be activated by switches.

You should get some ideas from Planning and Implementing a Program

...R