import java.util.Scanner;

public class  Exercise13_7

{

public static int binaryToDecimal(String s)

{

int sum=0;

int a;

for(int i=s.length()-1;i>=0;i–)

{
a=s.charAt(i)-48;

if(a!=0&&a!=1)

throw new ArithmeticException(” NO A BINARY”);

sum=(int) (sum+a*Math.pow(2,s.length()-1-i));

}

return sum;

}

public static void main(String[] args) 

{

Scanner input=new Scanner(System.in);

System.out.print(“Please input a binary string:”);

String binary=input.next();

try{

int decimal=binaryToDecimal(binary);

System.out.println(“\nThe decimal is “+decimal);

}

catch(ArithmeticException ex)

{

System.out.print(“Exception:The string is not a binaty string.”);

}

}

}