Python Program to Find Number of Digits in Nth Fibonacci Number

Python Program to Find Number of Digits in Nth Fibonacci Number

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Given a number N the task is to calculate the number of digits in the Nth Fibonacci Number.

Fibonacci Numbers:

Starting with 0 and 1, the next two numbers are simply the sum of the previous two numbers. The third number in this sequence, for example, is 0+1=1, hence the third number is 1. Similarly, the fourth number in this series will be 1+1=2, resulting in the fourth number being 2.
The Fibonacci Number Series is as follows: 0 1 1 2 3 5 8 13 21 and so on.

Examples:

Example1:

Input:

Given N=14

Output:

The Number of digits present in 14 th Fibonacci number is [ 3 ]

Example2:

Input:

Given N=23

Output:

The 23 th Fibonacci number is [ 17711 ]
The Number of digits present in 23 th Fibonacci number is [ 5 ]

Python Program to Find Number of Digits in Nth Fibonacci Number

Below are the ways to find the number of digits in the Nth Fibonacci Number.

Method #1: Using For Loop (Static Input)

Approach:

  • Give the number N as static input and store it in a variable.
  • Take a variable temp1 and initialize its value to 0.
  • Take another variable temp2 and initialize its value to 1.
  • Loop till N-2 using For loop.
  • Increment the value of temp1 by temp1 i.e temp1=temp1+temp2.
  • Swap the values of temp1,temp2 using the ‘,’ operator.
  • Check if the value of the given number N is 1 or not using the If statement.
  • If it is true then print the value of temp1 which is the value of the nth Fibonacci number.
  • Else print the value of temp2 which is the value of the nth Fibonacci number.
  • Calculate the number of digits by converting it to string.
  • Calculate the length of string which is the number of digits in the nth Fibonacci Number.
  • The Exit of the Program.

Below is the implementation:

# Give the number N as static input and store it in a variable.
numbr = 14
# Take a variable temp1 and initialize its value to 0.
temp1 = 0
# Take another variable temp2 and initialize its value to 1.
temp2 = 1
# Loop till N-2 using For loop.
for z in range(numbr-2):
    # Increment the value of temp1 by temp1 i.e temp1=temp1+temp2.
    temp1 = temp1+temp2
    # Swap the values of temp1,temp2 using the ',' operator.
    temp1, temp2 = temp2, temp1
# Check if the value of the given number N is 1 or not using the If statement.
if(numbr == 1):
  # If it is true then print the value of temp1 which is the value of the nth Fibonacci number
    print('The', numbr, 'th Fibonacci number is [', temp1, ']')
# Else print the value of temp2 which is the value of the nth Fibonacci number.
else:
    print('The', numbr, 'th Fibonacci number is [', temp2, ']')
# Calculate the number of digits by converting it to string.
stringnumbr = str(temp2)
# Calculate the length of string which is the number of digits in the nth Fibonacci Number.
nLen = len(stringnumbr)
print('The Number of digits present in', numbr,
      'th Fibonacci number is [', nLen, ']')

Output:

The 14 th Fibonacci number is [ 233 ]
The Number of digits present in 14 th Fibonacci number is [ 3 ]

Method #2: Using For Loop (User Input)

Approach:

  • Give the number N as user input using int(input()) and store it in a variable.
  • Take a variable temp1 and initialize its value to 0.
  • Take another variable temp2 and initialize its value to 1.
  • Loop till N-2 using For loop.
  • Increment the value of temp1 by temp1 i.e temp1=temp1+temp2.
  • Swap the values of temp1,temp2 using the ‘,’ operator.
  • Check if the value of the given number N is 1 or not using the If statement.
  • If it is true then print the value of temp1 which is the value of the nth Fibonacci number.
  • Else print the value of temp2 which is the value of the nth Fibonacci number.
  • Calculate the number of digits by converting it to string.
  • Calculate the length of string which is the number of digits in the nth Fibonacci Number.
  • The Exit of the Program.

Below is the implementation:

# Give the number N as user input using int(input()) and store it in a variable.
numbr = int(input('Enter some random nth number = '))
# Take a variable temp1 and initialize its value to 0.
temp1 = 0
# Take another variable temp2 and initialize its value to 1.
temp2 = 1
# Loop till N-2 using For loop.
for z in range(numbr-2):
    # Increment the value of temp1 by temp1 i.e temp1=temp1+temp2.
    temp1 = temp1+temp2
    # Swap the values of temp1,temp2 using the ',' operator.
    temp1, temp2 = temp2, temp1
# Check if the value of the given number N is 1 or not using the If statement.
if(numbr == 1):
  # If it is true then print the value of temp1 which is the value of the nth Fibonacci number
    print('The', numbr, 'th Fibonacci number is [', temp1, ']')
# Else print the value of temp2 which is the value of the nth Fibonacci number.
else:
    print('The', numbr, 'th Fibonacci number is [', temp2, ']')
# Calculate the number of digits by converting it to string.
stringnumbr = str(temp2)
# Calculate the length of string which is the number of digits in the nth Fibonacci Number.
nLen = len(stringnumbr)
print('The Number of digits present in', numbr,
      'th Fibonacci number is [', nLen, ']')

Output:

Enter some random nth number = 23
The 23 th Fibonacci number is [ 17711 ]
The Number of digits present in 23 th Fibonacci number is [ 5 ]

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