1	// Example 2.3 IfDemo.java
     2	//
     3	//
     4	// Copyright 2003 Bill Campbell and Ethan Bolker
     5	
     6	
     7	// A class illustrating the if-statement. A typical run:
     8	//
     9	// %> java IfDemo 
    10	// Enter an integer: 0
    11	// If 0 is negative, say hello:
    12	// isNegative is false
    13	// The integer 0 is zero
    14	// Finally: 0 is still nonnegative
    15	// because it's zero
    16	
    17	public class IfDemo 
    18	{
    19	    public static void main( String[] args ) 
    20	    {
    21	        Terminal terminal = new Terminal();  // for input and output
    22	
    23	        // Prompt for and read a single integer.
    24	        int var = terminal.readInt( "Enter an integer: " );
    25	        
    26	        // simple if statement
    27	        terminal.println( "If " + var + " is negative, say hello:" );
    28	        if (var < 0) {
    29	            terminal.println( "hello" );
    30	        }
    31	
    32	        // an if-else statement testing a boolean variable
    33	        boolean isNegative = ( var < 0 );
    34	        if (isNegative) {
    35	            terminal.println( "isNegative is true" );
    36	        }
    37	        else {
    38	            terminal.println( "isNegative is false" );
    39	        } 
    40	
    41	        // if-else-if statement
    42	        terminal.print( "The integer " + var + " is ");
    43	        if (var > 0) {
    44	            terminal.println("positive");
    45	        }
    46	        else if (var < 0) {
    47	            terminal.println( "negative" );
    48	        }
    49	        else { // just one case left!
    50	            terminal.println( "zero" );
    51	        }
    52	
    53	        // finally, nested if-(if)-else: note the indenting
    54	        terminal.print( "Finally: " + var + " is still ");
    55	        if (var >= 0) {
    56	            terminal.println("nonnegative");
    57	            if (var == 0 ) {
    58	                terminal.println("because it's zero ");
    59	            }
    60	        }
    61	        else {
    62	            terminal.println( "negative" );
    63	        }
    64	    }
    65	}