Convert Binary to Decimal
Convert a binary string (e.g. 1010) to its decimal integer value.
BeginnerTopic: Basic Python Programs
What You'll Learn
- Validating input format for binary strings
- Implementing positional numeral system evaluation
- Using loops to accumulate a numeric result
Python Convert Binary to Decimal Program
This program helps you to learn the fundamental structure and syntax of Python programming.
# Program to convert binary to decimal without using int(x, 2)
binary_str = input("Enter a binary number: ")
if not all(ch in '01' for ch in binary_str):
print("Invalid binary number.")
else:
decimal_value = 0
for ch in binary_str:
decimal_value = decimal_value * 2 + int(ch)
print(f"Decimal value of {binary_str} is {decimal_value}")Output
Enter a binary number: 1010 Decimal value of 1010 is 10
Step-by-Step Breakdown
- 1Read a string representing a binary number.
- 2Check that it only contains 0 and 1.
- 3Initialize decimal_value to 0.
- 4For each character, multiply decimal_value by 2 and add the bit.
- 5Print the final decimal value.
Understanding Convert Binary to Decimal
We interpret the binary string from left to right:
Starting from 0:
•Multiply current value by 2.
•Add the current bit (0 or 1).
This is equivalent to evaluating the positional value of each bit.
Note: To write and run Python programs, you need to set up the local environment on your computer. Refer to the complete article Setting up Python Development Environment. If you do not want to set up the local environment on your computer, you can also use online IDE to write and run your Python programs.