#include?
#include?“csd32.h“

void?koch（int?x?int?y?int?x2?int?y2）
{
??int?dx?=?x2?-?x?dy?=?y2?-?y;
??int?x13?=?x?+?dx?/?3?y13?=?y?+?dy?/?3;
??int?x23?=?x?+?dx?*?2?/?3?y23?=?y?+?dy?*?2?/?3;
??dx?=?x23?-?x13?dy?=?y23?-?y13;
??double?len?=?sqrt（dx?*?dx?+?dy?*?dy）;
??double?ang?=?atan2（dy?dx）?+?M_PI?/?3.0;
??int?x3?=?（int）（len?*?cos（ang）?+?x13）?y3?=?（int）（len?*?sin（ang）?+?y13）;
??if?（len?????csdLine（x?y?x2?y2）;
??else
??{
????koch（x?y?x13?y13）;
????koch（x13?y13?x3?y3）;
????koch（x3?y3?x23?y23）;
????koch（x23?y23?x2?y2）;
??}
}

int?main（void）
{
??int?x1?=?100?y1?=?400;
??int?x2?=?500?y2?=?400;
??int?x3?=?300?y3?=?54;
??csdInit（600?600?“Koch曲線“）;
??csdSetLineColor（RGB（0?0xFF?0））;
??csdSetPenWidth（2）;
??koch（x1?y1?x2?y2）;
??koch（x2?y2?x3?y3）;
??koch（x3?y3?x1?y1）;
??getch（）;
??csdClose（）;
??return?0;
}