Example: Conversion from binary to decimal

BinaryToDecimalDemo.java

/**
 * Example: Conversion from binary to decimal
 * Reference: https://www.rapidtables.com/convert/number/binary-to-decimal.html, https://byjus.com/maths/binary-to-decimal-conversion/
 * Sample Data:
 * 11 - 3
 * 111 - 7
 * 101 - 5
 * 1111 - 15
 * 1001 - 9
 *
 * Example
 * Given binary number = (1101)2
 * Now, multiplying each digit from MSB to LSB with reducing the power of the base number 2.
 * 1 × 2 raised to 3 + 1 × 2 raised to 2 + 0 × 2 raised to 1 + 1 × 2 raised to 0
 * = 8 + 4 + 0 + 1
 * = 13
 *
 * Thus, the equivalent decimal number for the given binary number (1101)2 is (13)10
 **/
public class BinaryToDecimalDemo {
    public static void main(String[] args) {
        int num=1101, rem, ans=0, cnt=0;
        while(num>0){
            rem=num%10;
            num=num/10;
            if(rem==0)
                ans = ans + (0* (int) Math.pow(2,cnt));
            else
                ans = ans + (1* (int) Math.pow(2,cnt));
            cnt++;
        }
        System.out.println(ans);
    }
}

public class BinaryToDecimalDemo {
public static void main(String[] args) {
int num=1101, rem, ans=0, cnt=0;
while(num>0){
rem=num%10;
num=num/10;
ans = ans + (rem* (int) Math.pow(2,cnt));
cnt++;
}
System.out.println(ans);
}
}