Coin

contract Coin {
    // The keyword "public" makes those variables
    // readable from outside.
    // declares a state variable of type address that
    // is publicly accessible,
    // does not allow any arithmetic operations. It is 
    // suitable for storing addresses of contracts or
    // keypairs belonging to external persons
    address public minter;
    mapping (address => uint) public balances;

Simple Storage

/**
 * collection of code (its functions) and data (its state)
 * that resides at a specific address on the Ethereum blockchain. 
 * think of it as a single slot in a database that can be
 * queried and altered by calling functions of the code that 
 * manages the database 
 * **/
contract SimpleStorage {
    //declares a state variable called storedData of type 
    //uint (unsigned integer of 256 bits)