Write a C# program: function to check whether a number is prime or not

Write a C# program: function to check whether a number is prime or not

In this article, we will discuss the concept of the Write a C# program: function to check whether a number is prime or not

In this post, we are going to learn how to write a program to check whether the given number is prime or not using the function, and display the result on the screen in JS language

Code to check prime number

Check the prime number in C# using function   – #1

In this program, the user is asked to enter values to variables “num”,  and the program checks whether the number is prime or not in C#.

Program 1

//function to check a number prime or not
using System;

public class CheckPrime
{
     public static bool Check_Prime(int num){//uer define function 
          for (int i=2; i<num; i++)
              if(num%i==0)
              return false;
         return true;
         
     }
    public static void Main(string[] args)//main
    {
        Console.Write ("Input a number: ");
        int n=Convert.ToInt32(Console.ReadLine());
        //Reading the input 
        if(Check_Prime(n))
        Console.WriteLine ("{0} is a prime number",n);
        else{
        Console.WriteLine ("{0} is not a prime number",n);}
         
    }
}

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

Case 1

Input a number: 31
31 is a prime number

 

Case 2

Input a number: 35
35 is not a prime number

 

Check the prime number in JS using function – #2

In this program, the user is asked to enter values to variables “num”, and the program checks whether the number is prime or not in C# using the function.

Program 2

//function to check a number prime or not
using System;

public class CheckPrime
{
     public static int Check_Prime(int number){//uer define function 
     int i;
          for (i=2; i<=number-1; i++){
              if(number%i==0){
              return 0;
              }
          }
        if(i==number){
              return 1;
              }
              return 0;
         
     }
    public static void Main(string[] args)
    {
        Console.Write ("Input a number: ");
        //ask input from the user
        int number=Convert.ToInt32(Console.ReadLine());
        //Reading the input
        int res= Check_Prime(number);
        //Calling the function and assign the result to var res
        if(res==0){
        Console.WriteLine ("{0} is not a prime number",number);}
        else{
        Console.WriteLine ("{0} is a prime number",number);}
         
    }
}

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

Case 1

Input a number: 61
61 is a prime number

 

Case 2

Input a number: 72
72 is not a prime number

 

 

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