// Yazzy Latif
// 06/26/2020
// TA: Grace Hopper
// Expressions Examples

// A few examples of using variables.
public class Variables {
   public static void main(String[] args) {
      int x; // Declaring
      x = 3; // Assigning
      
      double y = 5.2; // Declare and assign on one line.
      y = 4.1 + 3.7; // Can reassign variables and can use expressions as the value
      
      System.out.println("x is " + x); // x is 3
      x = x + 4; // Look up x, add 3, store result back into x
      x += 1; // Different syntax for x = x + 1
      x++;  // Also different syntax for x = x + 1
      System.out.println("x is " + x); // x is 9

      String word = "hello!"; // We can store Strings as well
      System.out.println(word);
      
      /*
         Some examples of common errors with variables.
         
         // Can't use a variable that has not been initialized to a value
         int number;
         System.out.println(number);
         
         // Can't use a variable before it's been declared
         // and initialized
         System.out.println(number2);
         int number2 = 5;
         
         // Can't declare a variable more than once
         int number3 = 102;
         int number3 = 45; // ERROR
         
         // Must store value of the correct type
         int number4 = 6.2; // ERROR
         int number4 = "6"; // ERROR
         
         double number5 = 10; // OKAY because 10 can be a double. 
      */
   }
}