如何每n次重置一个函数变量？

Question

我使用的是随机数生成功能,它的工作很好,但我需要重置功能变量nSeed每ñ倍,假设nSeed = 5323 ..我怎么能恢复到它的初始值5323每隔5个操作我不是确定怎么做..这是一个例子:

unsigned int PRNG()  

{  
    static unsigned int nSeed = 5323;  
    nSeed = (8253729 * nSeed + 2396403);  
    return nSeed  % 32767;
}  

int main()
{
   int count=0;  
   while(count<10)  
   {  
       count=count+1;  
       cout<<PRNG()<<endl;  

          if(count==5)
          {  
               nSeed= 5323;   //here's the problem, "Error nSeed wasn't declared in the scoop"
          } 
   }  
}  

注意:我需要在scoop中声明计数器,而不是在函数中.

Answer 1

只需使用另一个静态变量.例如

unsigned int PRNG()  
{
    const unsigned int INITIAL_SEED = 5323;
    static unsigned int i;
    static unsigned int nSeed;

    if ( i++ % 5 == 0 ) 
    {
        nSeed = INITIAL_SEED;
        i = 1;
    }

    nSeed = (8253729 * nSeed + 2396403);

    return nSeed  % 32767;
} 

另一种方法是使用参数声明函数.例如

unsigned int PRNG( bool reset )  
{
    const unsigned int INITIAL_SEED = 5323;
    static unsigned int nSeed = INITIAL_SEED;

    if ( reset ) nSeed = INITIAL_SEED;

    nSeed = (8253729 * nSeed + 2396403);

    return nSeed  % 32767;
}