这里有一个解决方案。创建一个返回随机数的函数并放置它 在main函数之外，使其具有全局性。希望这能有所帮助

#include <iostream>
#include <cstdlib>
#include <ctime>
int rollDie();
using std::cout;
int main (){
    srand((unsigned)time(0));
    int die1;
    int die2;
    for (int n=10; n>0; n--){
    die1 = rollDie();
    die2 = rollDie();
    cout << die1 << " + " << die2 << " = " << die1 + die2 << "\n";
}
system("pause");
return 0;
}
int rollDie(){
    return (rand()%6)+1;
}

使用模数可能会在随机数中引入偏置，这取决于随机数生成器。更多信息请看这个问题。当然，在随机序列中得到重复的数字是完全可能的。

尝试一些c++ 11特性以获得更好的分发:

#include <random>
#include <iostream>

int main()
{
    std::random_device dev;
    std::mt19937 rng(dev());
    std::uniform_int_distribution<std::mt19937::result_type> dist6(1,6); // distribution in range [1, 6]

    std::cout << dist6(rng) << std::endl;
}

有关c++ 11随机数的更多信息，请参阅此问题/答案。上面的方法并不是唯一的方法，但它是一种方法。

非常固执己见的回答

c++ <random>库违反了软件工程的最佳原则之一:“简单的事情做简单，复杂的事情，不寻常的事情可以更复杂一点。”

相反，他们甚至把简单和常见的用例变得过于复杂，只是因为他们患有文化疾病，害怕像“这还不够普遍”这样的评论。

As a result, now whenever you want a simple random number, you have to look into the documentation, read stack overflow with walls of text, glorifying this terrible design, instead of it just being an easy-to-remember one or 2 liner. (Common Lisp is more pragmatic: (random 5) yields uniformly distributed integers from 0..4 and (random 1.0) yields real numbers between 0.0..1.0. That is the most common use case and it is at your finger tips. If you need more sophisticated stuff, you have to find packages and libraries or do it yourself.)

只需计算一下全球范围内每个人浪费在理解标题及其内容上的时间累积的工时，就可以看到它有多糟糕。

即使我现在在浪费我的时间，写这个答案，你也在浪费时间，阅读它，只是因为他们创造了一个复杂的谜题，这与其他现代令人厌恶的东西相似，比如Vulkan API。

那么，如何应对呢?浪费一次时间，为自己最常见的用例编写一个头文件，然后在需要时重用它。

这段代码产生从n到m的随机数。

int random(int from, int to){
    return rand() % (to - from + 1) + from;
}

例子:

int main(){
    srand(time(0));
    cout << random(0, 99) << "\n";
}

这里有一个解决方案。创建一个返回随机数的函数并放置它 在main函数之外，使其具有全局性。希望这能有所帮助

#include <iostream>
#include <cstdlib>
#include <ctime>
int rollDie();
using std::cout;
int main (){
    srand((unsigned)time(0));
    int die1;
    int die2;
    for (int n=10; n>0; n--){
    die1 = rollDie();
    die2 = rollDie();
    cout << die1 << " + " << die2 << " = " << die1 + die2 << "\n";
}
system("pause");
return 0;
}
int rollDie(){
    return (rand()%6)+1;
}

如果你正在使用boost lib，你可以通过以下方式获得一个随机生成器:

#include <iostream>
#include <string>

// Used in randomization
#include <ctime>
#include <boost/random/mersenne_twister.hpp>
#include <boost/random/uniform_int_distribution.hpp>
#include <boost/random/variate_generator.hpp>

using namespace std;
using namespace boost;

int current_time_nanoseconds(){
    struct timespec tm;
    clock_gettime(CLOCK_REALTIME, &tm);
    return tm.tv_nsec;
}

int main (int argc, char* argv[]) {
    unsigned int dice_rolls = 12;
    random::mt19937 rng(current_time_nanoseconds());
    random::uniform_int_distribution<> six(1,6);

    for(unsigned int i=0; i<dice_rolls; i++){
        cout << six(rng) << endl;
    }
}

函数current_time_nanoseconds()给出以纳秒为单位的当前时间，用作种子。

下面是一个更通用的类，用于获取范围内的随机整数和日期:

#include <iostream>
#include <ctime>
#include <boost/random/mersenne_twister.hpp>
#include <boost/random/uniform_int_distribution.hpp>
#include <boost/random/variate_generator.hpp>
#include "boost/date_time/posix_time/posix_time.hpp"
#include "boost/date_time/gregorian/gregorian.hpp"


using namespace std;
using namespace boost;
using namespace boost::posix_time;
using namespace boost::gregorian;


class Randomizer {
private:
    static const bool debug_mode = false;
    random::mt19937 rng_;

    // The private constructor so that the user can not directly instantiate
    Randomizer() {
        if(debug_mode==true){
            this->rng_ = random::mt19937();
        }else{
            this->rng_ = random::mt19937(current_time_nanoseconds());
        }
    };

    int current_time_nanoseconds(){
        struct timespec tm;
        clock_gettime(CLOCK_REALTIME, &tm);
        return tm.tv_nsec;
    }

    // C++ 03
    // ========
    // Dont forget to declare these two. You want to make sure they
    // are unacceptable otherwise you may accidentally get copies of
    // your singleton appearing.
    Randomizer(Randomizer const&);     // Don't Implement
    void operator=(Randomizer const&); // Don't implement

public:
    static Randomizer& get_instance(){
        // The only instance of the class is created at the first call get_instance ()
        // and will be destroyed only when the program exits
        static Randomizer instance;
        return instance;
    }
    bool method() { return true; };

    int rand(unsigned int floor, unsigned int ceil){
        random::uniform_int_distribution<> rand_ = random::uniform_int_distribution<> (floor,ceil);
        return (rand_(rng_));
    }

    // Is not considering the millisecons
    time_duration rand_time_duration(){
        boost::posix_time::time_duration floor(0, 0, 0, 0);
        boost::posix_time::time_duration ceil(23, 59, 59, 0);
        unsigned int rand_seconds = rand(floor.total_seconds(), ceil.total_seconds());
        return seconds(rand_seconds);
    }


    date rand_date_from_epoch_to_now(){
        date now = second_clock::local_time().date();
        return rand_date_from_epoch_to_ceil(now);
    }

    date rand_date_from_epoch_to_ceil(date ceil_date){
        date epoch = ptime(date(1970,1,1)).date();
        return rand_date_in_interval(epoch, ceil_date);
    }

    date rand_date_in_interval(date floor_date, date ceil_date){
        return rand_ptime_in_interval(ptime(floor_date), ptime(ceil_date)).date();
    }

    ptime rand_ptime_from_epoch_to_now(){
        ptime now = second_clock::local_time();
        return rand_ptime_from_epoch_to_ceil(now);
    }

    ptime rand_ptime_from_epoch_to_ceil(ptime ceil_date){
        ptime epoch = ptime(date(1970,1,1));
        return rand_ptime_in_interval(epoch, ceil_date);
    }

    ptime rand_ptime_in_interval(ptime floor_date, ptime ceil_date){
        time_duration const diff = ceil_date - floor_date;
        long long gap_seconds = diff.total_seconds();
        long long step_seconds = Randomizer::get_instance().rand(0, gap_seconds);
        return floor_date + seconds(step_seconds);
    }
};