I am trying to find a function or expression which finds reads the resulting value and if it is a whole number. then ends program

Question

this is my program I hope you understand what I am trying to do.

   if (primeNum = int)
                        {
                            Console.WriteLine(" the number entered is not prime ");
                        }

Possible duplicate of [Check if number is prime number](http://stackoverflow.com/questions/15743192/check-if-number-is-prime-number) — nicovank, Oct 21 '16 at 03:27
no, it is not. just because i have written word prime in it does not mean I am looking for same thing. I need to find the function or an expression which checks the result if it is whole number or not. — ocgprogramers, Oct 21 '16 at 03:30
An int is always a whole number. If you declared primeNum as an int, it will always be a whole number, and of type int. — Max Hampton, Oct 21 '16 at 03:38

score 1 · Answer 1 · answered Oct 21 '16 at 03:38

If you want to know if it's a whole number, then round it and compare the numbers. If the number is a whole number, it will not change when it's rounded...so if the rounded version of the number is equal to the number itself, then it's a whole number. If they're different, then it's not a whole number:

double i = 1.2;
if (Math.Round(i, 0, MidpointRounding.AwayFromZero) == i) {
    //whole number
} else {
    //not a whole number
}

Isaac Hili · Answer 2 · 2017-07-04T14:46:30.880

1

private static bool IsWhole(double number)
{
    return (number % 1 == 0);
}

If Program.isWhole(5.67) returns true call System.Environment.Exit(0) to close application.

edited Jul 04 '17 at 14:46

answered Oct 21 '16 at 07:13

Isaac Hili

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score 0 · Answer 3 · edited May 23 '17 at 12:16

0

See this: How can I get the data type of a variable in C#?

and try:

if(primeNum.GetType() == typeof(int))

edited May 23 '17 at 12:16

Community

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answered Oct 21 '16 at 03:37

nicovank

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score 0 · Accepted Answer · answered Oct 21 '16 at 04:00

Try this program:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace primeCsharp
{
class Program
{
    static void Main(string[] args)
    {
        int n = 0;   // Number to be test for prime-ness
        int i = 2;   // Loop counter
        bool is_prime = true;   // Boolean flag...
                                // Assume true for now

        Console.WriteLine("Enter a number and press ENTER: ");
        n = Console.Read();

        // Test for a prime number by checking for divisiblity
        // by all whole numbers from 2 to sqrt(n).

        while (i <= Math.Sqrt(n))
        {
            if (n % i == 0)
            {   // If i divides n, 
                is_prime = false; // n ix not prime
                break;     // BREAK OUT OF THE LOOP NOW!
            }
            ++i;
        }

        // Print results

        if (is_prime)
        {
            Console.WriteLine("Number is prime.\n");
        }
        else
        {
            Console.WriteLine("Number is not prime.\n");
        }
    }
 }
}

thank you for showing your code. but what i am trying to do is to code this program without using "break;"command. but the program still loops through and does not include "Not Prime numbers". in the final result — ocgprogramers, Oct 22 '16 at 23:58

score 0 · Answer 5 · answered Oct 21 '16 at 07:33

0

You can check whether the number is equal to the value of its conversion to int, like this:

if (primeNum == (int)primeNum)

answered Oct 21 '16 at 07:33

Lajos Arpad

64,414
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I am trying to find a function or expression which finds reads the resulting value and if it is a whole number. then ends program

5 Answers5