求阶层

234.#include<iostream>

235.using namespace std;

236.int main()

237.{int fun(int);

238.int a,b,p,k,t;

239.cout<<"输入两个正整数:";

240.cin>>a>>b;

241.if(a<=0||b<=0)

242.{cout<<"输入错误,重新输入:";

245.cin>>a>>b;}

246.if(a<=b)

247.{t=a;

248.a=b;

249.b=t;}

250.k=a-b;

251.p=fun(a)/fun(b)*fun(k);

252.cout<<"p=m!/n!*(m-n)!="<<p<<endl;

253.return 0;

254.}

255.int fun(int n)

256.{int i,f=1;

257.for(i=1;i<=n;i++)

258.f=f*i;

259.return(f);

260.}