#include <stdio.h>
int main(){
    int n=9,i,j,x=0;
    for(i=0;i<n;i++){
        for(j=0;j<n;j++){
           if(x==j){
               printf("*");
           }else if(n-j-1==x||n-x-1==j){
               printf("*");
           }else {
                printf(" ");
           }
            x++;
        }
        printf("\n");
    }
    return 0;
}
//好像可以,没有试过,

我试试！

#include <stdio.h>
int main(int argc, char *argv[])
{
    char str[] = "         ";
    for(int i=0, j=sizeof str - 2; j>=0; ++i, --j)
    {
        str[i] = str[j] = '*';
        puts(str);
        str[i] = str[j] = ' ';
    }
    return 0;
}