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                             CHALLENGE 133

                                Andinus
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                               2021-10-04





Task 1 - Integer Square Root
════════════════════════════

  You are given a positive integer `$N'.

  Write a script to calculate the integer square root of the given
  number.

  Please avoid using built-in function. Find out more about it [here].

  ┌────
  │ Input: $N = 10
  │ Output: 3
  │
  │ Input: $N = 27
  │ Output: 5
  │
  │ Input: $N = 85
  │ Output: 9
  │
  │ Input: $N = 101
  │ Output: 10
  └────


[here] <https://en.wikipedia.org/wiki/Integer_square_root>

Raku
────

  • Program: <file:raku/ch-1.raku>

  Initial estimate is set to `$n +> 1', then we loop infinitely until
  previous 2 estimates are equal.

  ┌────
  │ my $x = $n +> 1;
  │ loop {
  │     given ($x + ($n / $x)) / 2 {
  │         last if $x == $_;
  │         $x = $_;
  │     }
  │ }
  │ put $x;
  └────


C
─

  • Program: <file:c/ch-1.c>

  `argv' holds the input & `argc' holds the number of inputs. The input
  should be a single integer so `argc' should be equal to 2. After
  checking for that, we check if valid value was passed.

  Loop until previous 2 estimates are equal.

  ┌────
  │ double x = num >> 1;
  │ for (;;) {
  │     double x_next = (x + (num / x)) / 2;
  │     if (x == x_next)
  │         break;
  │     x = x_next;
  │  }
  │ printf("%f\n", x);
  └────