1	// Example 3.2 joi/examples/ForDemo.java
     2	//
     3	//
     4	// Copyright 2003 Bill Campbell and Ethan Bolker
     5	
     6	// A class illustrating the For-statement.  A typical run:
     7	// 
     8	// %> java ForDemo
     9	// Enter integer: 7
    10	// 7 integers starting at 0: 0 1 2 3 4 5 6
    11	// First 7 Fibonacci numbers   (for): 1 1 2 3 5 8 13
    12	// First 7 Fibonacci numbers (while): 1 1 2 3 5 8 13
    13	// 49 @'s:
    14	// @@@@@@@
    15	// @@@@@@@
    16	// @@@@@@@
    17	// @@@@@@@
    18	// @@@@@@@
    19	// @@@@@@@
    20	// @@@@@@@
    21	
    22	public class ForDemo 
    23	{
    24	    public static void main( String[] args ) 
    25	    {
    26	        Terminal terminal = new Terminal();  // for input and output
    27	
    28	        // Prompt for and read a single integer.
    29	        int n = terminal.readInt( "Enter integer:" );
    30	
    31	        terminal.print( n + " integers starting at 0:" );
    32	        for ( int i = 0; i < n; i++ ) {
    33	            terminal.print( " " + i );  // all one one line
    34	        }
    35	        terminal.println();             // the newline
    36	
    37	        // Build Fibonacci numbers 1, 1, 2, 3, 5, 8, 
    38	        // by adding last two together to make the next
    39	        // Use three int variables and a loop:
    40	
    41	        int thisOne, lastOne, nextOne;
    42	        terminal.println( "First " + n + " Fibonacci numbers:" );
    43	
    44	        terminal.print("(for):               " );
    45	        thisOne = 1;
    46	        lastOne = 1;
    47	        for ( int i = 1; i <= n; i++ ) {
    48	            terminal.print( " " + lastOne );
    49	            nextOne = thisOne + lastOne;
    50	            lastOne = thisOne;
    51	            thisOne = nextOne;
    52	        }
    53	        terminal.println();
    54	
    55	        // Since i is never used in the body of the previous loop 
    56	        // we can count down to get the same output:
    57	        terminal.print("(for, counting down):" );
    58	        thisOne = 1;
    59	        lastOne = 1;
    60	        for ( int counter = n; counter > 0; counter-- ) {
    61	            terminal.print( " " + lastOne );
    62	            nextOne = thisOne + lastOne;
    63	            lastOne = thisOne;
    64	            thisOne = nextOne;
    65	        }
    66	        terminal.println();
    67	
    68	        // Replace the for loop with a while loop
    69	        terminal.print("(while):             " );
    70	        thisOne = 1;
    71	        lastOne = 1;
    72	        int i = 1;
    73	        while ( i <= n ) {
    74	            terminal.print( " " + lastOne );
    75	            nextOne = thisOne + lastOne;
    76	            lastOne = thisOne;
    77	            thisOne = nextOne;
    78	            i++;  
    79	        }
    80	        terminal.println();
    81	
    82	        terminal.println("Nested for loops: " + (n*n) + " @'s:" );
    83	        for ( int row = 1; row <= n ; row++ ) {
    84	            for ( int col = 1; col <= n; col++ ) {
    85	                terminal.print( " @" );
    86	            }
    87	            terminal.println();
    88	        }
    89	    }
    90	}