Unable to assign value and increment an int in C

Question

I have this program to generate armstrong numbers upto a given range. But the problem is that the range variable (n in this case) is somehow acting like a const. I cannot assign a value nor increment it... There are errors during compilation with gcc. The power function works fine (Same issue with pow() defind in math.h). I would like to know why this is happening to this code and the possible fix(es). Thank you

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

int power(int a, int b) {
    int c = 1;
    for(int i = 0; i < b; i++) {
        c *= a;
    }
    return c;
}

void main(void) {
    int sum, y, temp;
    printf("temp, y, sum, n\n");
    for(int n = 1; n < 100; n++) {
        temp = n;
        printf("%d ", temp);
        y = 0; // y to hold the number of digits of n
        while (n > 0) {
            n = n / 10;
            y++;
        }
        printf("%d ", y);

        n = temp;
        sum = 0;

        while(n > 0) {
            sum += power((n % 10), y);
            n = n / 10;
        }

        if (temp == sum) {
            printf("%d ", sum);
        }

        printf("%d\n", n);
    }
}

Output:

temp, y, sum, n
1 1 1 0
1 1 1 0
1 1 1 0
1 1 1 0
1 1 1 0
1 1 1 0
1 1 1 0
.
.
.

Answer 1

Are you not constantly dividing n by 10?

As n is an integer that starts as 1, and not a float, it would constantly set to 0.

Answer 2

Your second while(n > 0) loop effectively sets n=0 within the outer for loop. Did you want to use a second n = temp ?

Answer 3

before the last printf statement add: n = temp;
try you code like this:

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

int power(int a, int b) {
    int c = 1;
    for(int i = 0; i < b; i++) {
        c *= a;
    }
    return c;
}

void main(void) {
    int sum, y, temp;
    printf("temp, y, sum, n\n");
    for(int n = 1; n < 100; n++) {
        temp = n;
        printf("%d ", temp);
        y = 0; // y to hold the number of digits of n
        while (n > 0) {
            n = n / 10;
            y++;
        }
        printf("%d ", y);

        n = temp;
        sum = 0;

        while(n > 0) {
            sum += power((n % 10), y);
            n = n / 10;
        }

        if (temp == sum) {
            printf("%d ", sum);
        }
        n = temp;
        printf("%d\n", n);
    }
}

Answer 4

It is because the value of n is set to 0 outside the loop. Try the below code.

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

int power(int a, int b) {
    int c = 1;
    for(int i = 0; i < b; i++) {
        c *= a;
    }
    return c;
}

void main(void) {
    int sum, y, temp;
    printf("temp, y, sum, n\n");
    for(int n = 1; n < 100; n++) {
        temp = n;
        printf("%d ", temp);
        y = 0; // y to hold the number of digits of n
        while (n > 0) {
            n = n / 10;
            y++;
        }
        printf("%d ", y);

        n = temp;
        sum = 0;

        while(n > 0) {
            sum += power((n % 10), y);
            n = n / 10;
        }

        if (temp == sum) {
            printf("%d ", sum);
        }
        n = temp;
        printf("%d\n", n);
    }
}