Anybody Knows the Logic To Find Out a Number is Perfect Square or not ?

Manikavelu Velayutham

Does Anybody Knows the Logic To Find Out a Number is Perfect Square or not ? (Other than Newtons Method or Synthetic Division Method)

For Eg:- 4, 16, 36, 64 are Perfect Squares.

I will be giving the input as 441, logic should say whether its a Perfect Square or not.

It was a question asked in Amazon Interview.

6 Replies

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Vulpes15y ago
Accepted answer
Here's another way to do it:

using System;

class Program
{
static void Main()
{
Console.WriteLine("Enter a negative number to quit at any time\n");
int number;
bool isValid, isSquare;
while (true)
{
Console.Write("Enter an integer : ");
isValid = int.TryParse(Console.ReadLine(), out number);
if (!isValid) continue;
if (number < 0) return;
isSquare = IsSquare(number);
Console.WriteLine("{0} is {1} a perfect square\n", number, isSquare ? "" : "not");
}
}

static bool IsSquare(int number)
{
int next = number % 2;

do
{
if (next * next == number) return true;
next += 2;
}
while (next * next <= number);

return false;
}
}
0
raghu v15y ago
hi ,
try the follwoing code

static void Main(string[] args)
{
if (IsSquare(441))
{
Console.Write("Perfect");
}
else
{
Console.Write("Perfect");
}
Console.Read();
}
static bool IsSquare(int n)
{
int i = 1;
for (; ; )
{
if (n < 0)
return false;
if (n == 0)
return true;
n -= i;
i += 2;
}
}
0
Manikavelu Velayutham15y ago
Yes, you should not use Math.functions. It should be your own logic.

I already found a way to find out, But I want to see any other optimal way to find it.
0
Dorababu Meka15y ago
So you don't want to use Math. functions right
0
Manikavelu Velayutham15y ago
one condition missed in my question, addding it here.

Without using any In Built functions.
0
raghu v15y ago
hi

try this
double result = Math.Sqrt(numberToCheck);
bool isSquare = result%1 == 0;

to be more clear

double result = Math.Sqrt(16);
bool isSquare = result % 1 == 0;
if (isSquare)
{
Console.Write("Perfect");
}
Console.Read();

some thing like abv
0