程序代码：

#include ＜stdlib.h＞
#include ＜stdio.h＞
#include ＜time.h＞
#define N 1000000
int main()
{
srand((unsigned)time(NULL));
long xuan,che,huan=0,buhuan=0;
for(long i=0;i!=N;++i)
{
che=rand()%3;
xuan=rand()%3;
if(xuan==che) ++buhuan;
else ++huan;
}
printf("不换赢得车的次数：%ld，赢率%f\n换赢得车的次数%ld，赢率%f\n",buhuan,(double)buhuan/N,huan,(double)huan/N);
return 0;
}