写一个递归算法和一个迭代算法计算二项式系数：/m!(n-m)!

int jiecheng(int z)
{
if(z>=0)
{if(z==0)
return 1;
else if(z==1)
return 1
else
return z*jiecheng(z-1);
}
else
return -1;
}
int binconf(int x,int y)
{
if(x>y)
return jiecheng(x)/(jiecheng(y)*jiecheng(x-y));
else
return -1;
}
没测试过,不知对不对