Challenge 133

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

Raku

Program: 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: 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);