C++生成随机数——生成任意范围内的等概率随机数
以下是生成任意范围内的等概率随机数的程序,看不懂,请各位大神指教啊,希望能给出各语句尤其是核心语句的详解
,#include<iostream.h>
#include<time.h>
#include<stdlib.h>
const double MinProb=1.0/(RAND_MAX+1);
bool happened(double probability)//probability 0~1
{
if(probability<=0)
{
return false;
}
if(probability<MinProb)
{
return rand()==0&&happened(probability*(RAND_MAX+1));
}
if(rand()<=probability*(RAND_MAX+1))
{
return true;
}
return false;
}
long myrandom(long n)//产生0~n-1之间的等概率随机数
{
t=0;
if(n<=RAND_MAX)
{
long R=RAND_MAX-(RAND_MAX+1)%n;//尾数
t = rand();
while ( t > r )
{
t = rand();
}
return t % n;
}
else
{
long r = n%(RAND_MAX+1);//余数
if( happened( (double)r/n ) )//取到余数的概率
{
return n-r+myrandom(r);
}
else
{
return rand()+myrandom(n/(RAND_MAX+1))*(RAND_MAX+1);
}
}
}