Check if a given number is Pronic

The numbers that can be arranged to form a rectangle are called Rectangular Numbers (also known as Pronic numbers). The first few Pronic numbers are: 
0, 2, 6, 12, 20, 30, 42, 56, 72, 90, 110, 132, 156, 182, 210, 240, 272, 306, 342, 380, 420, 462 . . . . . . 
Pronic number is a number which is the product of two consecutive integers, that is, a number n is a product of x and (x+1). The task is to check and print Pronic Numbers in a range.
Examples :

Input  : 6
Output : Pronic Number
Explanation: 6 = 2 * 3 i.e 6 is a product
of two consecutive integers 2 and 3.

Input :56
Output :Pronic Number
Explanation: 56 = 7 * 8 i.e 56 is a product 
of two consecutive integers 7 and 8. 

Input  : 8
Output : Not a Pronic Number
Explanation: 8 = 2 * 4 i.e 8 is a product of 
2 and 4 which are not consecutive integers.

C++

// C/C++ program to check
// if a number is pronic
#include <iostream>
#include <math.h>
using namespace std;

// function to check
// Pronic Number
bool checkPronic(int x)
{

    for (int i = 0;
            i <= (int)(sqrt(x));
            i++)

        // Checking Pronic Number
        // by multiplying consecutive
        // numbers
        if (x == i * (i + 1))
        return true;

    return false;
}

// Driver Code
int main(void)
{
    // Printing Pronic Numbers
    // upto 200
    for (int i = 0; i <= 200; i++)
        if (checkPronic(i))
            cout << i << " ";

    return 0;
}

// This code is contributed
// by Nikita Tiwari.

Java

// Java program to check and
// Print Pronic Number upto 200
import java.io.*;
import java.util.*;
import java.math.*;

class GFG
{

    // function to check Pronic Number
    static boolean checkPronic(int x)
    {
        for (int i = 0;
             i <= (int)(Math.sqrt(x));
             i++)

            // Checking Pronic Number
            // by multiplying consecutive
            // numbers
            if (x == i * (i + 1))
                return true;

        return false;
    }

    // Driver Code
    public static void main(String[] args)
    {
        // Printing Pronic
        // Numbers upto 200
        for (int i = 0; i <= 200; i++)
            if (checkPronic(i))
                System.out.print(i + " ");
    }
}

// This code is contributed
// by Nikita Tiwari

Python3

# Python program to check
# and print Pronic Numbers
# upto 200
import math

# function to check
# Pronic Number
def checkPronic (x) :

    i = 0
    while ( i <= (int)(math.sqrt(x)) ) :

        # Checking Pronic Number
        # by multiplying consecutive
        # numbers
        if ( x == i * (i + 1)) :
            return True
        i = i + 1

    return False

# Driver Code

# Printing Pronic
# Numbers upto 200
i = 0
while (i <= 200 ) :
    if checkPronic(i) :
        print(i,end=" ")
    i = i + 1

# This code is contributed
# by Nikita Tiwari.

C#

// Java program to check and
// Print Pronic Number upto 200
using System;

class GFG
{

    // function to check
    // Pronic Number
    static bool checkPronic(int x)
    {
        for (int i = 0;
                 i <= (int)(Math.Sqrt(x));
                 i++)

            // Checking Pronic Number by
            // multiplying consecutive numbers
            if (x == i * (i + 1))
                return true;

        return false;
    }

    // Driver Code
    public static void Main()
    {
        // Printing Pronic
        // Numbers upto 200
        for (int i = 0; i <= 200; i++)
            if (checkPronic(i))
                Console.Write(i + " ");
    }
}

// This code is contributed by vt_m.

PHP

<?php
// PHP program to check
// if a number is pronic

// function to check
// Pronic Number
function checkPronic($x)
{

    for ($i = 0;
         $i <= (sqrt($x));
         $i++)

        // Checking Pronic Number
        // by multiplying consecutive
        // numbers
        if ($x == $i * ($i + 1))
        return true;

    return false;
}

// Driver Code

// Printing Pronic
// Numbers upto 200
for ($i = 0; $i <= 200; $i++)
    if (checkPronic($i))
        echo $i , " ";

// This code is contributed by Ajit
?>

Javascript

<script>

// Javascript program to check
// if a number is pronic

// function to check
// Pronic Number
function checkPronic(x)
{

    for (var i = 0;
            i <= parseInt(Math.sqrt(x));
            i++)

        // Checking Pronic Number
        // by multiplying consecutive
        // numbers
        if (x == i * (i + 1))
        return true;

    return false;
}

// Driver Code

// Printing Pronic Numbers
// upto 200
for (var i = 0; i <= 200; i++)
    if (checkPronic(i))
        document.write(i + " ");

// This code is contributed by noob2000
</script>

Output :

0 2 6 12 20 30 42 56 72 90 110 132 156 182

Time complexity: O( n sqrt n) to check for n numbers 
Auxiliary Space : O(1)