使用嵌套循环
```c
include
int main() {
int size = 5; // 五角星的大小
int i, j;
for (i = 1; i <= size; i++) {
for (j = 1; j <= 2 * size - i; j++) {
if (i == 1 || i == size || j == i || j == 2 * size - i) {
printf("* ");
} else {
printf(" ");
}
}
printf("\n");
}
return 0;
}
```
使用图形库
```c
include
int main() {
int gd = DETECT, gm;
initgraph(&gd, &gm, "C:\\TC\\BGI");
setbkcolor(RED);
setcolor(YELLOW);
line(320, 140, 320 + 100 * sin(P / 5), 240 + 100 * cos(P / 5)); // 五角星的中心点(320,240) 外接圆半径为100
line(320, 140, 320 - 100 * sin(P / 5), 240 + 100 * cos(P / 5));
line(320 + 100 * cos(P / 10), 240 - 100 * sin(P / 10), 320 - 100 * sin(P / 5), 240 + 100 * cos(P / 5));
line(320 + 100 * cos(P / 10), 240 - 100 * sin(P / 10), 320 - 100 * cos(P / 10), 240 - 100 * sin(P / 10));
line(320 + 100 * sin(P / 5), 240 + 100 * cos(P / 5), 320 - 100 * cos(P / 10), 240 - 100 * sin(P / 10));
floodfill(320, 240, YELLOW);
getch();
closegraph();
return 0;
}
```