用c语言：如何生成[a,b]范围内服从高斯分布的随机数？

用c语言：
如何生成[a,b]范围内服从高斯分布的随机数？
我会生成服从均匀分布的随机数
请大神指点，谢谢！

#include
#include
#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif

double drand() /* uniform distribution, (0..1] */
{
return (rand()+1.0)/(RAND_MAX+1.0);
}

double random_normal()
/* normal distribution, centered on 0, std dev 1 */
{
return sqrt(-2*log(drand())) * cos(2*M_PI*drand());
}

int main()
{

int i;
double rands[1000];
for (i=0; i<1000; i++)
rands[i] = constMean + constStandardDeviation * random_normal();
return 0;

}

 # include "stdio.h"
# include "math.h"
# include "stdlib.h"
# include "math.h"
# include "dos.h"
# define MAX_N 3000   /*这个值为N可以定义的最大长度*/
# define N 100        /*产生随机序列的点数，注意不要大于MAX_N*/

/*1.产生均匀分布的随机变量*/
void randa(float *x,int num); 

/*2.产生瑞利分布的随机变量*/
void randr(float *x,int num); 

/*3.产生标准高斯分布的随机变量*/
void randn(float *x,int num);

/*4.产生莱斯分布的随机变量*/
void randl(float *x, float a, float b, int num);

void fshow(char *name,float *x,int num);

/***************************************/
int main()
{

   float x[N];
   int i;

  // randa(&x,N);             //均匀分布
  // randr(&x,N);             //瑞利分布
  // randl(&x,10,10,N);       //莱斯分布
     randn(&x,N);             //高斯分布

/*此时x[N]表示要生成N个服从xx分布的的数组*/


   fshow("x",&x,N); /*显示该序列*/

   getch();
       return 0;

}
/***************函数定义************************/

/*产生服从均匀分布的随机变量*/
void randa(float *x,int num)
{
  int i;
  struct time stime;
  unsigned seed;
  gettime(&stime);
  seed=stime.ti_hund*stime.ti_min*stime.ti_hour;
  srand(seed);
  for(i=0;i<num;i++)
  {
     x[i]=rand();
     x[i]=x[i]/32768;
  }
}
/*产生服从瑞利分布的随机变量*/
void randr(float *x,int num)
{
  float x1[MAX_N];
  int i;
  struct time stime;
  unsigned seed;
  gettime(&stime);
  seed=stime.ti_hund*stime.ti_min*stime.ti_hour;
  srand(seed);
  for(i=0;i<num;i++)
  {
     x1[i]=rand();
     x[i]=x1[i]/32768;
     x[i]=sqrt(-2*log(x[i]));
  }

}
/*产生服从标准高斯分布的随机变量*/
void randn(float *x,int num)
{
  float x1[MAX_N],x2[MAX_N];
  int i;
  struct time stime;
  unsigned seed;
  gettime(&stime);
  seed=stime.ti_hund*stime.ti_min*stime.ti_hour;
  srand(seed);
  for(i=0;i<num;i++)
  {
     x1[i]=rand();
     x2[i]=rand();
     x1[i]=x1[i]/32768;
     x2[i]=x2[i]/32768;
     x[i]=sqrt(-2*log(x1[i]))*cos(x2[i]*M_PI);
  }

}
 /*产生服从莱斯分布的随机变量*/
void randl(float *x, float a, float b, int num)
{
  float x1[MAX_N],x2[MAX_N];
  float temp[MAX_N];
  int i;
  struct time stime;
  unsigned seed;
  gettime(&stime);
  seed=stime.ti_hund*stime.ti_min*stime.ti_hour;
  srand(seed);
  for(i=0;i<num;i++)
  {
     x1[i]=rand();
     x2[i]=rand();
     x1[i]=x1[i]/32768;
     x2[i]=x2[i]/32768;
     temp[i]=sqrt(-2*log(x1[i]))*cos(x2[i]*M_PI);
     x2[i]=sqrt(-2*log(x1[i]))*sin(x2[i]*M_PI);
     x1[i]=temp[i];
     x[i]=sqrt((a+x1[i])*(a+x1[i])+(b+x2[i])*(b+x2[i]));
  }

}

void fshow(char *name,float *x,int num)
{
  int i,sign,L;
  float temp;
  printf("\n");
  printf(name);
  printf(" = ");
  L=6;
  /*按照每行6个数据的格式显示*/
  for(i=0;i<num;i++)
  {
    temp=i/L;
    sign=temp;
    if((i-sign*L)==0) printf("\n");
    if(x[i]>0) printf(" %f   ",x[i]);
    else       printf("%f   ",x[i]);
  }
}