C++生成随机数

超级好用的C++随机数生成函数

一、下面的代码可以封装成头文件，文件名是util.h

#ifndef _OJ_DATA_UTIL_HEAD_
#define _OJ_DATA_UTIL_HEAD_
#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
namespace oj_tools {
void init() { srand(time(NULL)); } //初始化随机数种子
LL randLong() {                    //产生longlong类型的随机数
  LL x = rand();
  LL y = rand();
  return (x << 16) + y;
}

//产生double类型的随机数
inline double randDouble() { return (double)rand() / RAND_MAX; }

//产生范围为[start, end]范围的随机数
inline int randInt(int start, int end) {
  return (int)((end - start + 1) * randDouble() + start);
}

//产生范围为[start, end]正态分布的随机数size个
vector<int> randIntsNormalDistribution(int start, int end, int size = 10) {
  vector<int> v(size, 0);
  for (int i = 0; i < size; i++) {
    int tot = 0;
    for (int j = 0; j < 2; j++)
      tot += randInt(start, end);
    v[i] = tot / 2;
  }
  return v;
}

//产生范围为[start, end]泊松分布的随机数size个
vector<int> randIntsPossionDistribution(int start, int end, int size = 10) {
  vector<int> v(size, 0);
  for (int i = 0; i < size; i++) {
    int x = randInt(start, end);
    int y = randInt(start, end);
    v[i] = min(x, y);
  }
  return v;
}

//产生范围为[start, end]均匀分布的随机数size个
vector<int> randInts(int start, int end, int size = 10) {
  vector<int> v(size, 0);
  for (int i = 0; i < size; i++)
    v[i] = randInt(start, end);
  return v;
}

//产生范围为[start, end]等差数列的随机数size个
vector<int> equalDifferInts(int start, int end, int size = 10) {
  vector<int> v(size);
  int dif = (end - start + 1) / size;
  v[0] = start;
  for (int i = 1; i < size; i++) {
    v[i] = v[i - 1] + dif;
  }
  v[size - 1] = end;
  return v;
}

//产生范围为[start, end]等比数列的随机数size个
vector<int> equalRatioInts(int start, int end, int size = 10) {
  vector<int> v(size, 0);
  if (start == 0)
    ++start;
  double q = pow(1.0 * end / start, 1.0 / (size - 1));
  cout << q << endl;
  v[0] = start;
  for (int i = 1; i < size; i++)
    v[i] = (int)(v[i - 1] * q);
  v[size - 1] = end;
  return v;
}
} // namespace oj_tools
#endif

  

 

  
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二、主程序中的调用，随便写了一个测试程序makeInput.cpp

//头文件与主程序在同一文件夹下。否则要写相对路径，头文件名用双引号
#include "util.h"

int main(int argc, char const *argv[]) {
  oj_tools::init();//初始化随机数种子，如果用了命名空间，就要写在双冒号前面，如果不想用命名空间的写法，就在头文件中去掉命名空间
  int N = 10;
  std::vector<int> nn = oj_tools::equalRatioInts(1, 1000, N);//得到N个成等比数列的数，范围在【1,1000】
  std::vector<int> qq = oj_tools::equalRatioInts(1, 100000, N);
  for (int k = 0; k < N; k++) {
    ostringstream oss;
    oss << "data" << k << ".in";
    string str = oss.str();
    ofstream cout(str.c_str());
    int n = nn[k];
    int q = qq[k];
    if (n >= 800 && q >= 10000)
      q /= 10;
    cout << n << " " << q << endl;

    vector<int> v_op = oj_tools::randInts(0, 2, q);//产生范围为[start, end]均匀分布的随机数size个
    vector<int> v_x =
        oj_tools::randIntsNormalDistribution(-1000000000, 1000000000, q);
    vector<int> v_t = oj_tools::randInts(0, n - 1, q);

    for (int i = 0; i < q; i++) {
      int op = v_op[i];
      cout << op;
      if (op == 0) {
        int t = v_t[i];
        int x = v_x[i];
        cout << " " << t << " " << x << endl;
      } else {
        int t = v_t[i];
        cout << " " << t << endl;
      }
    }
  }
  return 0;
}

  

 

  
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文章来源: blog.csdn.net，作者：爱玲姐姐，版权归原作者所有，如需转载，请联系作者。

原文链接：blog.csdn.net/jal517486222/article/details/84553963