全班50个人，俩个人生日在同一天的概率是？C++

#include <ctime>
#include <iostream>
#include <algorithm>

using namespace std;

class birthday{
public:
    birthday(int n = 10000, int m = 50) : n(n), m(m){ }

    void test(){
        srand((unsigned)time(nullptr));
        int cnt = 0;
        for(int i = 0; i < n; ++i){
            bool *p = new bool[365];
            fill(p, p + 365, false);
            for(int j = 0; j < m; ++j){
                auto x = rand() % 365;
                if(p[x]){
                    cnt++;
                    break;
                }
                else{
                    p[x] = true;
                }
            }
            delete[] p;
        }
        cout << cnt * 1.0 / n << endl;
    }

private:
    int n; //实验次数
    int m; //人数
};


int main(){
    birthday a;
    a.test();

    return 0;
}