#include <stdio.h> int main() { int level, i, j, k; printf("请输入树的层数:"); scanf("%d", &level); for (i = 1; i <= level; i++) { //处理第i层 for (j = 0; j < i + 1; j++) { for (k = 1; k <= level - j; k++) { printf(" "); } for (k = 1; k <= 2 * j + 1; k++) { &nb