Algorithm

Binary to Decimal Conversion Algorithm:

  1. Read a binary number as input.
  2. Initialize a variable decimal to 0.
  3. Initialize a variable base to 1.
  4. Iterate through each digit of the binary number from right to left.
    • Multiply the current digit by the base.
    • Add the result to the decimal variable.
    • Multiply the base by 2.
  5. Print or return the decimal value as the result.

Decimal to Binary Conversion Algorithm:

  1. Read a decimal number as input.
  2. Initialize an empty string binary to store the binary representation.
  3. While the decimal number is greater than 0:
    • Take the remainder when dividing the decimal number by 2.
    • Convert the remainder to a character and prepend it to the binary string.
    • Divide the decimal number by 2.
  4. Print or return the binary string as the result.

 

Code Examples

#1 Code Example- Binary to Decimal Conversion Using Custom Method

Code - Java Programming

class Main {
    
  public static void main(String[] args) {

    // binary number
    long num = 110110111;

    // call method by passing the binary number
    int decimal = convertBinaryToDecimal(num);

    System.out.println("Binary to Decimal");
    System.out.println(num + " = " + decimal);
  }

  public static int convertBinaryToDecimal(long num) {
    int decimalNumber = 0, i = 0;
    long remainder;
    
    while (num != 0) {
      remainder = num % 10;
      num /= 10;
      decimalNumber += remainder * Math.pow(2, i);
      ++i;
    }
    
    return decimalNumber;
  }
}
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Output

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110110111 in binary = 439 in decimal

#2 Code Example- Binary to Decimal Conversion Using parseInt()

Code - Java Programming

class Main {
  public static void main(String[] args) {
    
    // binary number
    String binary = "01011011";
    
    // convert to decimal
    int decimal = Integer.parseInt(binary, 2);
    System.out.println(binary + " in binary = " + decimal + " in decimal.");
  }
}
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Output

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01011011 in binary = 91 in decimal.

#3 Code Example- Decimal to Binary Conversion using Custom Method

Code - Java Programming

class Main {

  public static void main(String[] args) {

    // decimal number
    int num = 19;
    System.out.println("Decimal to Binary");

    // call method to convert to binary
    long binary = convertDecimalToBinary(num);

    System.out.println("\n" + num + " = " + binary);
    }

  public static long convertDecimalToBinary(int n) {

    long binaryNumber = 0;
    int remainder, i = 1, step = 1;

    while (n!=0) {
      remainder = n % 2;
        System.out.println("Step " + step++ + ": " + n + "/2");

        System.out.println("Quotient = " + n/2 + ", Remainder = " + remainder);
        n /= 2;

        binaryNumber += remainder * i;
        i *= 10;
    }
    
    return binaryNumber;
    }
}
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Output

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Decimal to Binary
Step 1: 19/2
Quotient = 9, Remainder = 1
Step 2: 9/2
Quotient = 4, Remainder = 1
Step 3: 4/2
Quotient = 2, Remainder = 0
Step 4: 2/2
Quotient = 1, Remainder = 0
Step 5: 1/2
Quotient = 0, Remainder = 1
19 = 10011

#4 Code Example- Decimal to Binary Conversion using toBinaryString()

Code - Java Programming

class Main {
  public static void main(String[] args) {
    
    // decimal number 
    int decimal = 91;
    
    // convert decimal to binary
    String binary = Integer.toBinaryString(decimal);
    System.out.println(decimal + " in decimal = " + binary + " in binary.");
  }
}
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Output

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91 in decimal = 1011011 in binary.
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Demonstration

Java Programing Example to Convert Binary Number to Decimal and vice-versa-DevsEnv