Java Convert Binary to Decimal

public class BinaryToDecimalExample1{  
public static void main(String args[]){  
String binaryString="1010";  
int decimal=Integer.parseInt(binaryString,2);  
System.out.println(decimal);  
}}  

Output:

10

Let's see another example of Integer.parseInt() method.

public class BinaryToDecimalExample2{  
public static void main(String args[]){  
System.out.println(Integer.parseInt("1010",2));  
System.out.println(Integer.parseInt("10101",2));  
System.out.println(Integer.parseInt("11111",2));  
}}  

Output:

10
21
31

Java Binary to Decimal conversion: Custom Logic

We can convert binary to decimal in java using custom logic.

public class BinaryToDecimalExample3{    
public static int getDecimal(int binary){  
    int decimal = 0;  
    int n = 0;  
    while(true){  
      if(binary == 0){  
        break;  
      } else {  
          int temp = binary%10;  
          decimal += temp*Math.pow(2, n);  
          binary = binary/10;  
          n++;  
       }  
    }  
    return decimal;  
}  
public static void main(String args[]){    
System.out.println("Decimal of 1010 is: "+getDecimal(1010));  
System.out.println("Decimal of 10101 is: "+getDecimal(10101));  
System.out.println("Decimal of 11111 is: "+getDecimal(11111));  
}}    

Output:

Decimal of 1010 is: 10
Decimal of 10101 is: 21
Decimal of 11111 is: 31