Ethereum's contract system can be used with any programming languages in existence. The most popular example of this is Solidity, which was developed specifically for Ethereum and has since been ported over to other platforms like Bitcoin and Hyperledger. However, there are more than 20 different languages available!
The two main purposes of these contracts are: 1) To create self-executing agreements between parties 2) To store information about an application or database
Ethereum is the most famous platform for smart contracts, but it's not the only one. Ethereum Classic (ETC) is a fork of Ethereum that came into being following the infamous DAO hack in 2016. Despite this fact, ETC and ETH use completely different contract systems with different programming languages.
