Armstrong Number in Range in C, C++, Java & Python – Code with Explanation & Examples in Short and Simple

   

C Program

int power(int b, int e) {
    int r = 1;
    while (e--) r *= b;
    return r;
}

void armstrong(int low, int high) {
    for (int n = low; n <= high; n++) {
        int sum = 0, x = n, d = 0;
        for (int t = n; t; t /= 10) d++;
        for (int t = n; t; t /= 10)
            sum += power(t % 10, d);
        if (sum == n) printf("%d ", n);
    }
}

C Output

Input:  
1, 500 

Output:  
1 2 3 4 5 6 7 8 9 153 370 371 407

C++ Program

int power(int b, int e) {
    int r = 1;
    while (e--) r *= b;
    return r;
}

void armstrong(int low, int high) {
    for (int n = low; n <= high; n++) {
        int sum = 0, x = n, d = 0;
        for (int t = n; t; t /= 10) d++;
        for (int t = n; t; t /= 10)
            sum += power(t % 10, d);
        if (sum == n) cout << n << " ";
    }
}

C++ Output

Input:  
1, 500 

Output:  
1 2 3 4 5 6 7 8 9 153 370 371 407

JAVA Program

int power(int b, int e) {
    int r = 1;
    while (e-- > 0) r *= b;
    return r;
}

void armstrong(int low, int high) {
    for (int n = low; n <= high; n++) {
        int sum = 0, x = n, d = 0;
        for (int t = x; t > 0; t /= 10) d++;
        for (int t = x; t > 0; t /= 10)
            sum += power(t % 10, d);
        if (sum == n) System.out.print(n + " ");
    }
}

JAVA Output

Input:  
1, 500 

Output:  
1 2 3 4 5 6 7 8 9 153 370 371 407

Python Program

def armstrong(low, high):
    for n in range(low, high + 1):
        d = len(str(n))
        if sum(int(i) ** d for i in str(n)) == n:
            print(n, end=" ")

Python Output

Input:  
1, 500 

Output:  
1 2 3 4 5 6 7 8 9 153 370 371 407

In-Depth Explanation

Example

Let's try number 153:

It contains 3 digits.

So we calculate 1³ + 5³ + 3³ = 1 + 125 + 27 = 153

Because the result is the same as the original number, 153 is an Armstrong Number.

Now, if we're trying a range like 1 to 500, the program loops through every number, determines its digit count, raises each digit to that count, adds them up, and verifies if the sum is the same as the number.

Real-Life Analogy

Imagine every digit as a player adding to the team's total strength (the number). But every player's strength is elevated to the number of players (digits) there are. If their total strength exactly reproduces the original number, it's an equal superhero team — an unusual and powerful configuration. That's what makes an Armstrong Number "special."

Why It Matters

This exercise elegantly combines digit manipulation, power functions, and conditional logic. You learn:

How to loop through a range

Get digits out of numbers

Employ mathematics such as exponentiation

Utilize nested loops and functions effectively

You also learn to handle varying digit lengths, which is usually a necessary skill in actual problems such as encryption, digital verifications, and checksum checks.

What You'll Learn from This

You enhance your knowledge of:

Nested number manipulations

Effective loop engineering

How to compute powers manually (without built-ins)

Dealing with digit-level logic (very handy for binary, octal, or decimal conversion)

You are also exposed to:

Range-based testing

Pattern recognition

Constructing and applying helper functions (such as power)

Interview Relevance and Real Projects

Armstrong Number in a range is frequently asked in:

Freshers' interviews

College entry tests

Programming tests

It tests:

Loop control

Mathematical skills

Ability to handle multi-digit logic

Real-world applications include:

Validation algorithms (digital lock systems)

Checksum and ID pattern recognition

Math education software

Game logic where power/points system follows this logic

SEO-Optimized Explanation

Armstrong Number in a range is one of the most common programming exercises in C, C++, Java, and Python that deals with verifying which numbers in a specified range fulfill an interesting mathematical property: the number is equal to the sum of its digits powered by the count of digits. This reasoning is applied extensively to construct programming building blocks for digit-based operations, loops, conditionals, and power functions. It's perfect for coding interviews, competitive programming, and training for working with mathematical patterns within a range. Armstrong numbers mastery enables programmers to improve algorithmic thinking and learn to decompose and examine numbers programmatically.