using System;

class BinToDec2
{
    public static void Main(string[] args)
    {
        {
            String bin_1;//creates string to store binary number
            Console.WriteLine("Welcome, to.....");
            Console.WriteLine("Binary to Decimal Conversion, Version 2.0");//Introduces program
            Console.WriteLine();//blank line
            Console.WriteLine("Please enter the positive binary number you wish to convert to decimal.");
            //requests input from user
            bin_1 = Console.ReadLine();//stores input form user for binary number
            int I=bin_1.Length;//counts characters in length from binary number
            int dec_1;//creates integer to store decimal number
            int P=1;//let P equal to 2^1
            dec_1 = 0;//gives decimal a beginning value of 0
            while(true){//starts loop
                if(I==0) break;//break loop once I = 0
                I=I - 1;//subtracts 1 from I so, that once at 0, will break loop
                if (bin_1[I] == '1')//If binary digit is 1, do the following
                dec_1 = dec_1 + P;//if binary digit is one, add dec_1 to P
                P=P * 2;//updates P to be equal to 2^I
            }//ends loop
            Console.WriteLine();//blank line
            Console.WriteLine();//blank line
            Console.WriteLine("Your Binary Number of {0}", bin_1);//repeats users binary number
            Console.WriteLine("is equal to the Decimal Number {0}.", dec_1.ToString() );
            //displays solution to user
            Console.WriteLine();//blank line
            Console.WriteLine();//blank line
            Console.WriteLine();//blank line
            Console.WriteLine("Thank You For Using Binary to Decimal Conversion.");//thanks user
            Console.WriteLine("Hit the Enter Key to Exit.");//instructs user to hit enter to end
            Console.ReadLine();//waits for input to end program
        }
    }
}