C编程，数组无法正确打印

Question

So for class we are doing some encryption/ decryption algorithms with prime numbers. I am in the first part of making the program. I am trying to get the program to check if a number is prime or not. After this, I want the program to store all prime numbers before that number in an array called prime_array. And I was trying to get those results to print out on the screen. It's not working the way I intended. I'm later going to use this in decryption of something a bit more complex. Just wandering if anyone could see what part of my code is causing the issues.

Code:

  #include <stdio.h>

    int main()
    {
        int n;
        int prime;
        int prime_array[1000];
        int prime_answer;
        int j=0;

        printf("enter a number for n : ");
        scanf_s("%d", &n);   

        if (n % 2 == 1)
        {
            printf("Number is prime.");
            getchar();
            getchar();

            for (int i = 0; i <= n; i++)
            {
                if (n - 1 % 2 == 1)
                {
                    n--;
                    prime_array[j] = n;
                    j++;    
                }
                else
                {
                    // do nothing
                }    
            }    
        }
        else if (n % 2 == 0)
        {
            printf("Number is not prime.");
            getchar();
            getchar();

        }

        for (int k = 0; k<= 10; k++)
        {
            printf("\n\n %d",prime_array[k]);
            if (k == 10);
            {
                getchar();
                getchar();       
            }       
        }        
}

Answer 1

Problem is this condition-

if (n - 1 % 2 == 1)

This exression is treated as (n-(1 % 2))==1 , because % has higher precedence than - ,therefore , 1 % 2 is evaluated first .As 1 % 2 is 1 and expression become n-1 ,so condition will not be true until n is 2 ( not as you would desire ) .

You need to write like this -

if ((n - 1) % 2 == 1)