题解 | #箭形图案#

#include <stdio.h>

int main() {
	int a;
	int i, j, k, l, m, n;
	while (scanf("%d", &a) != EOF)
	{
		for (i = 0; i < a + 1; i++)
		{
			for (j = 0; j <a*2-i*2; j++)
				printf(" ");
			for (k = 0; k < i+1; k++)
				printf("*");
			printf("\n");
		}
		for (l = 0; l < a; l++)
		{
			for (m = 0; m <2+l * 2; m++)
				printf(" ");
			for (n = 0; n < a-l; n++)
				printf("*");
			printf("\n");
		}
	}
	return 0;
}