1	// Example 2.1 While1Demo.java
     2	//
     3	//
     4	// Copyright 2003 Bill Campbell and Ethan Bolker
     5	
     6	// A class for illustrating the while-statement.  A typical run:
     7	// 
     8	// %> java While1Demo
     9	// Enter integer (a negative to stop): 4
    10	// 4 is non-negative.
    11	// Enter integer (a negative to stop): -3
    12	// 
    13	// Enter integer (a negative to stop): 5
    14	// 5 is non-negative.
    15	// Enter integer (a negative to stop): -2
    16	// Finally, enter integer you want to count to: 12
    17	// Count 1 to 12: 1 2 3 4 5 6 7 8 9 10 11 12
    18	
    19	public class While1Demo
    20	{
    21	    public static void main( String[] args ) 
    22	    {
    23	        Terminal terminal = new Terminal();  // for input and output
    24	        
    25	        // while tests a condition
    26	        int n = terminal.readInt("Enter integer (a negative to stop): ");
    27	        while ( n >= 0 ) {
    28	            terminal.println( n + " is non-negative." );
    29	            n = terminal.readInt("Enter integer (a negative to stop): ");
    30	        }
    31	        terminal.println();
    32	
    33	        // while tests a boolean variable
    34	        boolean more = true;
    35	        while ( more ) {
    36	            n = terminal.readInt("Enter integer (a negative to stop): ");
    37	            if ( n >= 0 ) {
    38	                terminal.println( n + " is non-negative." );
    39	            }
    40	            else {
    41	                more = false;
    42	            }
    43	        }
    44	
    45	        // while used for counting
    46	        n = terminal.
    47	            readInt("Finally, enter integer you want to count to: ");
    48	        int i = 1;
    49	        terminal.print( "Count 1 to " + n + ":" );
    50	        while ( i <= n ) {
    51	            terminal.print( " " + i );
    52	            i++;  //  same as i = i + 1
    53	        }
    54	        terminal.println();
    55	    }
    56	}