c++ - Generating a multinomial distribution -

i trying write/find code piece/function gives multinomial distribution given number , probability array, function:

mult(n, pp[]) 

for example, pp={0.3, 0.2, 0.5}, (pp can have variable sizes, 2 10 elements).

mult(10, pp[]) 

giving outputs like:

1,1,8 3,1,6 2,3,5 

when called in different occasions.

i can think of following using gsl when called repeatedly in different occasions not good. understand code piece quoted below not one, looking forward suggestions have better one. thanks.

std::vector<int> mult(int numb, std::vector<double> prob_array) {     const gsl_rng_type * t2;     gsl_rng * r2;     srand(); // srand(time(null));      unsigned int seed2 = 1234567; // rand();     gsl_rng_env_setup();      t2 = gsl_rng_default;     r2 = gsl_rng_alloc (t2);     gsl_rng_set (r2, seed2);      size_t k = prob_array.size();      double ppp[k]; // probability array      for(int ii=0; ii<prob_array.size(); ++ii) {         ppp[ii] =  prob_array[ii];     }      unsigned int mult_op[k];     gsl_ran_multinomial(r2, k, numb, ppp, mult_op);     std::vector<int> multi;     for(int ii=0; ii<kk; ++ii ){         multi.push_back(mult_op[ii]);     }     return multi; }