Python Program to Find Armstrong Number in an Interval


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An Armstrong number, also known as narcissistic number, is a number that is equal to the sum of the cubes of its own digits. For example, 371 is an Armstrong number since 371 = 3*3*3 + 7*7*7 + 1*1*1.

Source Code:


# Program to ask the user for a range and display all Armstrong numbers in that interval

# take input from the user
lower = int(input("Enter lower range: "))
upper = int(input("Enter upper range: "))

for num in range(lower,upper + 1):
   # initialize sum
   sum = 0

   # find the sum of the cube of each digit
   temp = num
   while temp > 0:
       digit = temp % 10
       sum += digit ** 3
       temp //= 10

   if num == sum:
       print(num)

Output:


Enter lower range: 100
Enter upper range: 1000
153
370
371
407



Here, we ask the user for the interval in which we want to search for Armstrong numbers. We scan through the interval and display all the numbers that meet the condition. We can see that there are 4 three digit Armstrong numbers.