Python program to convert decimal to binary number

Converting decimal numbers to binary is a fundamental programming task. Python provides both manual and built-in approaches to achieve this conversion.

Problem Statement

Given a decimal number, we need to convert it into its binary representation.

Using Recursive Approach

The recursive method divides the number by 2 repeatedly and prints the remainders in reverse order −

Algorithm

DecToBin(num):
    if num > 1:
        DecToBin(num // 2)
    print num % 2

Example

def DecimalToBinary(num):
    if num > 1:
        DecimalToBinary(num // 2)
    print(num % 2, end='')

# Test the function
dec_val = 35
print("Binary representation of", dec_val, "is: ", end='')
DecimalToBinary(dec_val)

Binary representation of 35 is: 100011

Using Built-in bin() Function

Python's bin() function provides a direct way to convert decimal to binary −

def decimalToBinary(n):
    return bin(n).replace("0b", "")

# Test the function
decimal_number = 35
binary_result = decimalToBinary(decimal_number)
print(f"Binary representation of {decimal_number} is: {binary_result}")

Binary representation of 35 is: 100011

Using format() Function

Another built-in approach uses the format() function with binary format specifier −

def decimalToBinaryFormat(n):
    return format(n, 'b')

# Test the function
decimal_number = 35
binary_result = decimalToBinaryFormat(decimal_number)
print(f"Binary representation of {decimal_number} is: {binary_result}")

Binary representation of 35 is: 100011

Comparison

Conclusion

Use bin() or format() for efficient built-in conversion. The recursive approach helps understand the mathematical process of decimal-to-binary conversion.