C语言怎么输出这个数字图案呀

Question

Answer 1

#include<stdio.h>
int num;
void main()
{
    int a,i,b,c;
    printf("n=");
    scanf_s("%d", &a);
    for (i=1;i<=a;i++)
    {
        b = a-i;
        c = a-1+i-b;
        while (b--)printf(" ");
        while (c--)printf("%d",i);
        printf("\n");
    }
    for (i = a-1; i >= 1; i--)
    {
        b = a - i;
        c = a-1-b+i;
        while (b--)printf(" ");
        while (c--)printf("%d", i);
        printf("\n");
    }
}