C#: Check a positive integer and return true if it contains a number 2

Last update on June 28 2025 12:53:53 (UTC/GMT +8 hours)

Check If Number Contains 2

Write a C# Sharp program to check a positive integer and return true if it contains a number 2.

Visual Presentation:

C# Sharp: Basic Algorithm Exercises - Check a positive integer and return true if it contains a number 2.

Sample Solution:

C# Sharp Code:

using System; // Importing the System namespace for basic functionality
using System.Collections; // Importing collections for non-generic interfaces
using System.Collections.Generic; // Importing collections for generic interfaces
using System.Linq; // Importing LINQ for querying collections
using System.Text; // Importing classes for handling strings
using System.Threading.Tasks; // Importing classes for handling asynchronous tasks

namespace exercises // Defining a namespace called 'exercises'
{
   class Program // Defining a class named 'Program'
   {
      static void Main(string[] args) // The entry point of the program
      {               
         // Output the result of the 'test' method with different integer values
         Console.WriteLine(test(123)); 
         Console.WriteLine(test(13)); 
         Console.WriteLine(test(222)); 
      }                  

      // Method to check if an integer contains the digit '2'
      public static bool test(int n)
      {
         while (n > 0) // Loop through each digit of the input integer 'n'
         {
            if (n % 10 == 2) return true; // Check if the last digit is equal to '2'
            n /= 10; // Remove the last digit by dividing 'n' by 10
         }
         return false; // Return false if '2' is not found in 'n'
      }    
   } 
}

Sample Output:

True
False
True

Flowchart:

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