C++rand函数采用的LCG

$$seed_n+1 = (seed_n × 214013 + 2531011) mod 2^{31}$$
$$r_n+1 = seed_n+1 >>16,0$$

手动代码实现

#include <bits/stdc++.h>
using namespace std;
unsigned int seed_next = 0;
int LCG_seed()
{
    seed_next = (seed_next * 214013 + 2531011) % (1<<31);
    return seed_next>>16 & ((1<<15)-1);
} 
void test(int seed1,int seed2)
{
    srand(seed1);
    cout<<"种子为1的VC++rand伪随机数："<<endl; 
    for (int i=0;i<5;i++) cout<<rand()<<" ";
    cout<<endl;
    seed_next = seed1;
    cout<<"种子为1的手动实现rand"<<endl;
    for (int i=0;i<5;i++) cout<<LCG_seed()<<" ";
    cout<<endl;
    puts("------------------------------------");
    srand(seed2);
    cout<<"种子为100的VC++rand伪随机数："<<endl;  
    for (int i=0;i<5;i++) cout<<rand()<<" ";
    cout<<endl;
    seed_next = seed2;
    cout<<"种子为100的手动实现rand"<<endl;
    for (int i=0;i<5;i++) cout<<LCG_seed()<<" ";
    cout<<endl;
}
int main()
{
    int seed1 = 1, seed2 = 100;
    test(seed1,seed2);
    return 0;

}