if Statement

• The basic format for an if statement is:

  if (logical-expression)
      statement-executed-if-true
  

• The basic format for an if-then-else statement is:

  if (logical-expression)
      statement-executed-if-true
  else 
      statement-executed-if-false
  

• In addition to having a single statement (Statements), you can use a compound statement.
  

• A compound-statement is any number of statements enclosed in curly braces.
  
  
• Each statement within the curly braces is executed, in order.
  
  
• For instance, in this code:

  if (x1 == x2)
  {
      System.out.println("**Warning x1 equals x2");
      answer = 0;
  }
  else
  {
      answer = ((y2 - y1) / (x2 - x1));
  }
  

  When x1 and x2 have the same value, first the print statement is executed, and then the assignment statement is executed.