C language: hollow square pattern

Hollow square pattern ： Topic link

#include<stdio.h>
int main()
{
    
    int n=0;
    while(scanf("%d",&n)!=EOF)
    {
    
        for(int i=0;i<n;i++)
        {
    
            if(i==0||i==n-1)
            {
    
                for(int j=0;j<n;j++)
                {
    
                    printf("* ");
                }
                printf("\n");
            }
            else
            {
    
                printf("*");
                for(int j=0;j<2*n-3;j++)
                {
    
                    printf(" ");
                }
                printf("*");
                printf("\n");
            }
        }
    }
}

What we need to pay attention to is , Multiple input shaping , Then we need to use a cycle scanf To receive ,scanf and getchar equally , If there is nothing to receive, return one -1（EOF)

Then there is the first line and the last line , The space in the middle is （n-1）+（n-2）=2n-3 individual
n-1 It's the original two * The number of spaces between ,n-2 It's the original * The position of becomes a space .