{"id":807,"date":"2024-10-19T13:21:35","date_gmt":"2024-10-19T07:51:35","guid":{"rendered":"https:\/\/codexplained.in\/?p=807"},"modified":"2025-11-24T15:40:14","modified_gmt":"2025-11-24T10:10:14","slug":"armstrong-numbers-between-two-intervals","status":"publish","type":"post","link":"https:\/\/codexplained.in\/?p=807","title":{"rendered":"Armstrong Numbers between Two Intervals."},"content":{"rendered":"
\n#include <stdio.h>\n#include <math.h>\n\nint main() {\n    int lower, upper, num, originalNum, remainder, n = 0, result = 0;\n\n    \/\/ Asking the user to enter the lower and upper bounds\n    printf("Enter the lower bound: ");\n    scanf("%d", &lower);\n    printf("Enter the upper bound: ");\n    scanf("%d", &upper);\n\n    \/\/ Loop to go through all numbers in the interval\n    for (num = lower; num <= upper; num++) {\n        originalNum = num;\n        result = 0;\n        n = 0;\n\n        \/\/ Find the number of digits in the number\n        while (originalNum != 0) {\n            originalNum \/= 10;\n            ++n;\n        }\n\n        originalNum = num;\n\n        \/\/ Calculate the sum of nth powers of its digits\n        while (originalNum != 0) {\n            remainder = originalNum % 10;\n            result += pow(remainder, n);\n            originalNum \/= 10;\n        }\n\n        \/\/ Check if the number is an Armstrong number\n        if (result == num) {\n            printf("%d is an Armstrong number.\\n", num);\n        }\n    }\n\n    return 0;\n}\n\n<\/pre><\/div>\n\n\n
Explanation:<\/h2>\n\n\n\n
    \n
  1. Variables:<\/strong>\n
      \n
    • lower<\/code>, upper<\/code>: Store the user-defined range of numbers.<\/li>\n\n\n\n
    • num<\/code>: Current number being checked.<\/li>\n\n\n\n
    • originalNum<\/code>, remainder<\/code>: Used for calculations on num<\/code>.<\/li>\n\n\n\n
    • n<\/code>: Number of digits in num<\/code>.<\/li>\n\n\n\n
    • result<\/code>: Stores the sum of the digits raised to the power of n<\/code>.<\/li>\n<\/ul>\n<\/li>\n\n\n\n
    • User Input:<\/strong>\n
        \n
      • User enters the lower and upper bounds for the interval.<\/li>\n<\/ul>\n<\/li>\n\n\n\n
      • For Loop:<\/strong>\n
          \n
        • Loops through each number in the interval.<\/li>\n<\/ul>\n<\/li>\n\n\n\n
        • Digit Count:<\/strong>\n
            \n
          • Calculates how many digits are in the current number (num<\/code>).<\/li>\n<\/ul>\n<\/li>\n\n\n\n
          • Sum of Digits Raised to Power n<\/code>:<\/strong>\n
              \n
            • For each digit in the number, the program raises it to the power of n<\/code> and adds the result to result<\/code>.<\/li>\n<\/ul>\n<\/li>\n\n\n\n
            • Armstrong Check:<\/strong>\n
                \n
              • If the sum of the digits raised to their powers equals the original number, it’s printed as an Armstrong number.<\/li>\n<\/ul>\n<\/li>\n\n\n\n
              • Output:<\/strong>\n
                  \n
                • Prints Armstrong numbers found between the two intervals.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n
                  Output:<\/h2>\n\n\n\n
                  Enter the lower bound: 100\nEnter the upper bound: 500\n153 is an Armstrong number.\n370 is an Armstrong number.\n371 is an Armstrong number.\n407 is an Armstrong number.<\/code><\/pre>\n