Question

出于某种原因，我每次都会得到6。我知道另一种做随机骰子的方法，但我想学习如何使用deafult_random_engine。

#include <iostream>
#include <string>
#include <random>
#include <ctime>

using namespace std;

int main()
{
    default_random_engine randomGenerator(time(0));
    uniform_int_distribution<int> diceRoll(1, 6);

    cout << "You rolled a " << diceRoll(randomGenerator) << endl;
}

但是这段代码适用于time(0)。

#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;

int main()
// dice roll
{
    srand(time(0));
    for(int x = 1; x < 2; x++){
        cout << 1+(rand()%6) << endl;
    }
    return 0;
}

Answer 1

几乎可以肯定，time(0)是罪魁祸首。

你应该选择这样的方法：

#include <iostream>
#include <string>
#include <chrono>
#include <random>
#include <ctime>

using namespace std;

int main() {
    default_random_engine randomGenerator(std::random_device{}());
    // OR:
    // default_random_engine randomGenerator(
    //  (unsigned) chrono::system_clock::now().time_since_epoch().count());

    uniform_int_distribution<int> diceRoll(1, 6);

    cout << "You rolled a " << diceRoll(randomGenerator) << endl;

    return 0;
}

虽然您的原始代码始终在我的系统上生成6，但这个代码似乎更“冒险”：

pax> for i in {1..10}; do ./qq ; sleep 1 ; done
You rolled a 5
You rolled a 5
You rolled a 6
You rolled a 1
You rolled a 6
You rolled a 5
You rolled a 2
You rolled a 3
You rolled a 5
You rolled a 4

Answer 2

 #include <iostream>
 #include <string>
 #include <random>
 #include <ctime>

 using namespace std;

 int main()
 {
  mt19937 randomGenerator(time(0));
  uniform_int_distribution<int> diceRoll(1, 6);

  cout << "You rolled a " << diceRoll(randomGenerator) << endl;
 }

骰子滚动不起作用C ++ deafult_random_engine

2 个答案: