C++生成随机浮点数的示例代码

//返回time_t类型的 当前时间的时间戳
time_t time (time_t* timer);

//传入一个种子，为伪随机数生成器初始化
void srand (unsigned int seed);

//得到一个整形伪随机数
int rand (void);

#include <stdio.h>
#include <time.h>
#include <stdlib.h>

int main()
{
    int arr[10] = { 0 };
    
    for (int i = 0; i < 10; ++i)
    {
        srand((unsigned int)time(NULL));
        //两个相减是为了出现负的随机数，使测试范围更广
        arr[i] = (rand() % 100 + 1) - (rand() % 100 + 1);
        
        printf("%d ", arr[i]);
    }
    
    return 0;
}

#include <stdio.h>
#include <time.h>
#include <stdlib.h>
#include <windows.h>


int main()
{
    int arr[10] = { 0 };

    for (int i = 0; i < 10; ++i)
    {
        Sleep(1000);
        srand((unsigned int)time(NULL));
        arr[i] = (rand() % 100 + 1) - (rand() % 100 + 1);

        printf("%d ", arr[i]);
    }

    return 0;
}

#include <stdio.h>
#include <time.h>
#include <stdlib.h>

int main()
{
    int arr[10] = { 0 };

    srand((unsigned int)time(NULL));
    for (int i = 0; i < 10; ++i)
    {
        arr[i] = (rand() % 100 + 1) - (rand() % 100 + 1);

        printf("%d ", arr[i]);
    }

    return 0;
}

template <class IntType = int> 
class uniform_int_distribution;

// IntType
// An integer type. Aliased as member type result_type.
// By default, this is int.

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

int main()
{
    //产生[1, 100]左闭右闭区间的随机整数
	uniform_int_distribution<int> u(1, 100);
	default_random_engine e;
    //为随机数引擎设置随机种子，若不设置每次生成的随机数相同(可以创建时设置)
    //类似srand的用法,相同的种子生成的随机数相同
    //default_random_engine e(time(NULL));
    e.seed(time(NULL));

	for (size_t i = 0; i < 10; ++i)
	{
		cout << u(e) << " ";
	}
	cout << endl;

	return 0;
}

template <class RealType = double> 
class uniform_real_distribution;

// RealType
// A floating-point type. Aliased as member type result_type.
// By default, this is double.

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

int main()
{
    //生成[-1, 1]范围随机浮点数
    //模板参数只能是浮点类型（float，double， long double）
	uniform_real_distribution<double> u(-1, 1);
    default_random_engine e(time(NULL));

	for (size_t i = 0; i < 10; ++i)
	{
		cout << u(e) << " ";
	}
	cout << endl;
    
	return 0;
}

template <class RealType = double> 
class normal_distribution;

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

int main()
{
    //生成符合均值为10，标准差为2的随机数
	normal_distribution<double> u(10, 2);
    default_random_engine e(time(NULL));
    
	for (size_t i = 1; i <= 100; ++i)
	{
		printf("%-9.6lf ", u(e));
		if (i % 10 == 0)
		{
			cout << endl;
		}
	}
    cout << endl;

	return 0;
}

class bernoulli_distribution;

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

int main()
{
	// 生成1的概率为0.7
	bernoulli_distribution u(0.7); 
    default_random_engine e(time(NULL));

	for (int i = 0; i < 10; i++) {
		cout << u(e) << " ";
	}
    cout << endl;

	return 0;
}