Diamond pattern in C programming encountered an error in last loop, this program always provide me a different output, how is this possible anyhow? [closed]

Question

This program always provide me a different output, I'm confused how is this possible. Error is in the last loop which is under if conditional statement but don't know what is it?

#include <stdio.h>

int main()
{
    int n;
    printf("Enter the number upto which the pattern is to be printed \n ");
    scanf("%d", &n);

    /* Upside inverted V */

    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j <= n - i; j++)
        {
            printf(" ");
        }

        for (int k = 1; k <= i; k++)
        {
            printf("%d", k);
        }

        if (i > 1)
        {
            for (int l = i - 1; l > 0; l--)
            {
                printf("%d", l);
            }
        }

        printf("\n");
    }

    // down V part

    for (int x = n - 1; x >= 1; x--)
    {
        for (int y = n; y > x; y--)
        {
            printf(" ");
        }

        for (int z = 1; z <= x; z++)
        {
            printf("%d", z);
        }

        if (x > 1)
        {
            for (int w = x - 1; w >= 1; w--)
            {
                printf("%d", &w);
            }
        }

        printf("\n");
    }

    return 0;
}

Removing the last loop get me run one third of my program or the pattern which I had wanted.

Answer 1

If you enabled compiler warnings, the compiler would have shown you a warning in the line

printf("%d", &w);

You are printing the address of the variable instead of the variable value. Because w is a variable on the stack, that address can change if you rerun the program. Remove the & operator and it should print the correct value.

Answer 2

In your last for loop there is printf("%d", &w);. The &w is incorrect, you have to use printf("%d", w); instead. It prints every time a different value beacause you are printing not the value in w, but where the value is stored.

I think you can improve your code with functions like the following and use them instead of repeating the same type of for.

void printNTimesChar(int n, char c){
  for(int i=0;i<n;i++){
    printf("%c", c);
  } 
} 
void printNTimesInt(int n, int value){
   for(int i=0;i<n;i++){
     printf("%d", value);
   }
}