Math.sqrt in java - identify if its a complete sqrt number or not?

Question

I am looking to identify method in Java 8 which says square root of any number is complete or not.

For ex:

Math.sqrt(25) gives 5.0
Math.sqrt(49) gives 7.0
Math.sqrt(30) gives 5.477225575051661

So when given number is complete sqrt, need to written true else false, how can we simply do this?

Can you define what you mean by "complete"? Is `Math.sqrt(1.44)` complete? — Joachim Sauer, Jul 02 '21 at 12:23
What do you mean by "complete"? Do you mean "square root is an integer"? Note that `sqrt` is the function name, but the name to use when talking about the math is "square root". — Alan, Jul 02 '21 at 12:24
Complete means its gives value washout decimal values. Why you're downvoting it ? I have clearly given example — Jeff Cook, Jul 02 '21 at 12:25
*"I have clearly given example"* - but not generic enough examples. E.g. the root of 1.44 is 1.2 which may or may not be accepted by your code. — luk2302, Jul 02 '21 at 12:26
@JeffCook "washout"? Do you mean "without". Computing is about getting details right and clear. Sorry if English is not your first language. — Alan, Jul 02 '21 at 12:27
@JeffCook: three example don't make a specification. If your question was totally clear, I wouldn't have posted my comment abd it wouldn't have been upvoted. — Joachim Sauer, Jul 02 '21 at 12:27

score 2 · Answer 1 · answered Jul 02 '21 at 12:25

2

You could compare the square root to the floor of the square root and check if they're equal:

public static boolean hasCompleteSqrt(double d) {
    double sqrt = Math.sqrt(d);
    return sqrt == Math.floor(sqrt);
}

answered Jul 02 '21 at 12:25

Mureinik

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score 1 · Accepted Answer · answered Jul 02 '21 at 12:25

1

if the ceil or floor is equal to the number...

x  =  Math.sqrt(25);

if (x==Math.ceil(x)||x==Math.floor(x))

answered Jul 02 '21 at 12:25

ΦXocę 웃 Пepeúpa ツ

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If `x` is an integer then `Math.ceil()` is the same value as `Math.floor()`, no need to check both. Or am I missing something here? – Joachim Sauer Jul 02 '21 at 12:28

score 0 · Answer 3 · answered Jul 02 '21 at 12:28

0

You can use Math.floor:

double notInteger = Math.sqrt(30);
double integer = Math.sqrt(25);

notInteger == Math.floor(notInteger); // false
integer == Math.floor(integer); // true

answered Jul 02 '21 at 12:28

tomrlh

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score 0 · Answer 4 · answered Jul 02 '21 at 12:34

you can check if square root of number is whole number or not as below

 if((Math.sqrt(25)) % 1 == 0) {
                System.out.println("it is whole number");
            } else {
                System.out.println("it is not whole number");
            }

Math.sqrt in java - identify if its a complete sqrt number or not?

4 Answers4