C# programming exercises - examples with solutions

If number contains 3

Write a method that checks if given number (positive integer) contains digit 3. Do not convert number to other type. Do not use built-in functions like Contains(), StartsWith(), etc.

Expected input and output

IfNumberContains3(7201432) → true IfNumberContains3(87501) → false

Click here to see example solution

using System;

namespace CSharpExercises.Exercises.Conditional_statements
{
    class IfNumberContains3Task
    {
        public static bool IfNumberContains3(int number)
        {
            while (number > 0)
            {
                if (number % 10 == 3)
                {
                    return true;
                }

                number /= 10;
            }

            return false;
        }

        public static void Main()
        {
            Console.WriteLine(IfNumberContains3(5384562)); // true
            Console.WriteLine(IfNumberContains3(0));       // false
            Console.WriteLine(IfNumberContains3(390462));  // true
        }
    }
}