C# program to check if a number is prime or not

C# program to check if a number is prime or not

In this tutorial, we will discuss the concept of the C# program to check whether a Number is Prime or Not

In this post, we are going to learn how to check whether a number is prime or not  in Csharp programming language with Example program

 

Prime number

The number that can be divided by 1 and itself ony. it is called a prime number

for Example 2,3,5,7,11,13…

Example to check whether a Number is Prime or Not

Check the prime number – variable initialization

In this program, we will initialize the variable as a positive number, then it will check whether the given number is a prime number or not, using the for loop in C# language.

Program 1

//c# program to check if a number is prime or not

using System;
public class CheckPriume{

    public static void Main(string[] args)
    {
        int num=7,count=0;
        for (int i=1; i<=num; i++){
            if(num%i==0){
                count++;
            }
            }
        if(count==2){
        Console.WriteLine ("{0} is a prime number",num);
    }else{
    Console.WriteLine ("{0} is  noy a prime number",num);
}
}
}

When the above code is executed, it produces the following result

7 is a prime number

 

Check the prime number –  Entered by the user

This program allows the user to enter a positive number then it will check whether the given number is a prime number or not, using the for loop in C# language.

Program 2

//c# program to check if a number is prime or not
//Entered by user
using System;
public class CheckPriume{

    public static void Main(string[] args)
    {
        int num,count=0,i;
         Console.WriteLine ("Enter the number to check prime or not");
         num=int.Parse( Console.ReadLine());
         int m=num/2;
        for (i=2; i<=m; i++){
            if(num%i==0){
               Console.WriteLine ("{0} is not a prime number",num);
               count=1;
               break;
            }
            }
        if(count==0){
    Console.WriteLine ("{0} is  a prime number",num);
}
}
}

When the above code is executed, it produces the following result

 

Case 1

Enter the number to check prime or not
17
17 is a prime number

 

Case 2

Enter the number to check prime or not
10
10 is not a prime number

 

 

 

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