如何打印出一个空心三角形》
*
* *
*****

main()
{
int h=3,i,j,l,r;
l=r=h;
for(i=1;i<=h;i++)
{printf("\n");
for(j=1;j<=2*h-1;j++)
{if(i!=h) {if(j==l||j==r) printf("*"); else printf(" ");}
else printf("*");
}
l--;r++;
}
getch();
}

能帮我做个三角形,让它没隔1秒,旋转45度吗?谢了

printf("空心三角形\r\n");

用time.h

#include <stdio.h>
int main(void)
{
        int i,j,num;
        printf("Lines you want: \n");
        scanf("%d",&num);
        for (i = 1; i <num; i++) {
                for (j = 0;j < i; j++) {
                        if (j>0 && j < i - 1) {
                                printf(" ");
                        } else {
                                printf("*");
                        }
                }
                printf("\n");
        }
                for (j = 0; j < i; j++)
                        printf("*");
                printf("\n");
}

运行结果：
Lines you want:
5
*
**
* *
*  *
*****

如果要旋转的用C是浪费，Qt就很简单了，图形库大把的函数能行！