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Ruby program to convert the decimal number to binary using recursion

Last Updated : December 15, 2025

Problem Solution

In this program, we will read an integer number from the user and get the equivalent binary number using recursion.

Program/Source Code

The source code to convert the decimal number to binary using recursion is given below. The given program is compiled and executed successfully.

# Ruby program to convert the decimal number 
# to binary using recursion

def dec2bin(num)
    if num == 0
        return 0;
    else
        return num % 2 + 10 * dec2bin(num / 2);
    end
end

print "Enter number: ";
number = gets.chomp.to_i;  

result = dec2bin(number);

print "Binary equivalent is: ",result;

Output

Enter number: 8
Binary equivalent is: 1000

Explanation

In the above program, we read an integer number from the user. Then we converted the given decimal number to the binary using recursive function dec2bin(). Then we printed the result.

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