Collatz.java


Below is the syntax highlighted version of Collatz.java from §2.3 Recursion.


/******************************************************************************
 *  Compilation:  javac Collatz.java
 *  Execution:    java Collatz n
 *  
 *  Print the collatz sequence of n.
 *
 *  % java Collatz 6
 *  6 3 10 5 16 8 4 2 1 
 *
 *  % java Collatz 27
 *  27 82 41 124 62 31 94 47 142 71 214 107 322 161 484 242 121 364 182
 *  91 274 137 412 206 103 310 155 466 233 700 350 175 526 263 790 395
 *  1186 593 1780 890 445 1336 668 334 167 502 251 754 377 1132 566 283
 *  850 425 1276 638 319 958 479 1438 719 2158 1079 3238 1619 4858 2429
 *  7288 3644 1822 911 2734 1367 4102 2051 6154 3077 9232 4616 2308
 *  1154 577 1732 866 433 1300 650 325 976 488 244 122 61 184 92 46 23
 *  70 35 106 53 160 80 40 20 10 5 16 8 4 2 1 
 * 
 *  % java Collatz 35
 *  35 106 53 160 80 40 20 10 5 16 8 4 2 1 
 *
 *  % java Collatz 256
 *  256 128 64 32 16 8 4 2 1 
 *
 ******************************************************************************/

public class Collatz {
    public static void collatz(int n) {
        StdOut.print(n + " ");
        if (n == 1) return;
        else if (n % 2 == 0) collatz(n / 2);
        else collatz(3*n + 1);
    }

    public static void main(String[] args) {
        int n = Integer.parseInt(args[0]);
        collatz(n);
        StdOut.println();
    }

}



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Last updated: Tue Aug 30 09:58:33 EDT 2016.