{"id":1002,"date":"2024-10-19T13:29:24","date_gmt":"2024-10-19T07:59:24","guid":{"rendered":"https:\/\/codexplained.in\/?p=1002"},"modified":"2025-11-24T15:38:11","modified_gmt":"2025-11-24T10:08:11","slug":"check-armstrong-number","status":"publish","type":"post","link":"https:\/\/codexplained.in\/?p=1002","title":{"rendered":"Check Armstrong Number"},"content":{"rendered":"
\n#include <stdio.h>\n#include <math.h>\n\nint main() {\n    int number, originalNumber, remainder, digits = 0, sum = 0;\n\n    \/\/ Get user input\n    printf("Enter an integer: ");\n    scanf("%d", &number);\n\n    originalNumber = number; \/\/ Store the original number for later comparison\n\n    \/\/ Calculate the number of digits\n    while (originalNumber != 0) {\n        originalNumber \/= 10; \/\/ Divide the number by 10\n        digits++; \/\/ Increase digit count\n    }\n\n    originalNumber = number; \/\/ Reset original number for the next calculation\n\n    \/\/ Calculate the sum of each digit raised to the power of 'digits'\n    while (originalNumber != 0) {\n        remainder = originalNumber % 10; \/\/ Get last digit\n        sum += pow(remainder, digits); \/\/ Add the power of the digit to sum\n        originalNumber \/= 10; \/\/ Remove last digit\n    }\n\n    \/\/ Check if the original number is equal to the sum\n    if (sum == number) {\n        printf("%d is an Armstrong number.\\n", number);\n    } else {\n        printf("%d is not an Armstrong number.\\n", number);\n    }\n\n    return 0; \/\/ Indicate successful completion\n}\n\n<\/pre><\/div>\n\n\n
Explanation:<\/h2>\n\n\n\n
Including Libraries<\/strong>:<\/p>\n\n\n\n
Including Libraries:

c

#include <stdio.h>
#include <math.h>

We include stdio.h for input and output and math.h for mathematical functions like pow.

Main Function:

c

int main() { ... }

This is where the execution starts. It returns an integer indicating how the program finished.

Variable Declaration:

c

int number, originalNumber, remainder, digits = 0, sum = 0;

Here, number stores the user input, originalNumber is used for calculations, remainder stores each digit, digits counts the total digits, and sum accumulates the powers of the digits.

User Input:

c

printf(\"Enter an integer: \");
scanf(\"%d\", &number);

We prompt the user for an integer and read it into number.

Calculating Number of Digits:

c

while (originalNumber != 0) {
    originalNumber \/= 10; \/\/ Divide the number by 10
    digits++; \/\/ Count the digits
}

This loop counts the digits by dividing the number by 10 until it becomes zero.

Resetting originalNumber:

c

originalNumber = number; \/\/ Reset original number

We reset originalNumber to its original value for the next loop.

Calculating the Armstrong Sum:

c

while (originalNumber != 0) {
    remainder = originalNumber % 10; \/\/ Get last digit
    sum += pow(remainder, digits); \/\/ Add the power of the digit
    originalNumber \/= 10; \/\/ Remove last digit
}

In this loop, we extract each digit, raise it to the power of the total digit count, and add it to sum.

Checking the Armstrong Condition:

c

if (sum == number) {
    printf(\"%d is an Armstrong number.\\n\", number);
} else {
    printf(\"%d is not an Armstrong number.\\n\", number);
}

Finally, we compare the calculated sum with the original number and display the result.<\/pre>\n\n\n\n
OUTPUT:<\/h2>\n\n\n\n
Enter an integer: 153
153 is an Armstrong number.<\/p>\n