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BJP4 Exercise 12.19: countBinary

Language/Type: Java recursion recursive backtracking
Author: Marty Stepp (on 2016/09/08)

Write a method countBinary that accepts an integer n as a parameter and that prints all binary numbers that have n digits in ascending order, printing each value on a separate line. All n digits should be shown for all numbers, including leading zeros if necessary. You may assume that n is non-negative. If n is 0, a blank line of output should be produced. Do not use a loop in your solution; implement it recursively.

Call Output 
countBinary(1);
 
0
1

countBinary(2);
 
00
01
10
11

countBinary(3);
 
000
001
010
011
100
101
110
111

Hint: It may help to define a private helper method that accepts different parameters than the original method. In particular, consider building up a set of characters as a String for eventual printing.

Type your solution here:


This is a method problem. Write a Java method as described. Do not write a complete program or class; just the method(s) above.

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