Python Program to Convert Decimal to Octal

Problem: Write a Program in Python to convert a decimal number into its corresponding octal representation.

Example:

Input:  8
Output: 10

Input:  15
Output: 17

Convert Decimal to Octal in Python using Loop

The standard way to convert a decimal to an octal is to divide the decimal by 8 until it reduces to 0.

After the division is over, if we stack the remainders in a bottom-up manner the result value will be the equivalent octal number.

decimal = int(input("Enter a decimal number: "))
octal = 0
ctr = 0
temp = decimal  #copying number
 
#computing octal using while loop
while(temp > 0):
    octal += ((temp%8)*(10**ctr))  #Stacking remainders
    temp = int(temp/8)             #updating dividend
    ctr += 1
       
print("Binary of {x} is: {y}".format(x=decimal,y=octal))

Output:

Enter a decimal number: 15
Binary of 15 is: 17

Convert Decimal to Octal in Python using Recursion

To convert decimal into octal using recursion, we pass the quotient (dividend/8) to the next recursive call and output the remainder value (dividend%8).

We repeat the process until the number reduces to zero (i.e. until decimal > 0).

Since recursion implements stack, the remainders get printed in a bottom-up manner and we get the equivalent octal number.

def dectoOct(decimal):
    if(decimal > 0):
        dectoOct((int)(decimal/8))
        print(decimal%8, end='')
        
decimal = int(input("Enter a decimal number: "))
print("Octal: ", end='')
dectoOct(decimal)

Output:

Enter a decimal number: 8
Octal: 10

Convert Decimal to Octal using oct()

The built-in Python method oct() method returns the octal representation of the decimal number passed as a parameter.

It returns an octal number in the form of 0oxyz, where xyz is the actual octal number value.

>>> print(oct(15))
0o17

Comment below your doubts or suggestions if you have any.