Question

How to print all 3 digits armstrong numbers in C

Answer 1

// Armstrong = a number that equals the sum of its digits, 
//             each raised to a power of the number of digits
// For example 153, it's an Armstrong number because 1^3 + 5^3 + 3^3 = 153

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

bool armstrong(int n) {
    int reminder = 0, sum = 0, total_digits = log10(n) + 1;
    int temp = n;
    
    while (temp > 0) {
        reminder = temp % 10;
        sum += (float)pow((float)reminder, (float)total_digits);
        temp = temp / 10;
    }
    
    if (sum == n) {
        return true;
    }
        
    return false;
}

int main(void) {
    for (int i = 100; i <= 999; i++) {
        if (armstrong(i)) {
            printf("%d, ", i);
        }
    }

    return 0;
}




/*
run:

153, 370, 371, 407, 

*/

 

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