/************************************************************* FileName : rand.c FileFunc : 产生随机整型正整数 Version : V0.1 Author : Sunrier Date : 2012-05-11 Descp : Linux下产生随机正整数(范围1到RAND_MAX) *************************************************************/#include <stdio.h>#include <stdlib.h>int MyRand( void ){struct timeval tpstart;int iRet;gettimeofday(&tpstart,NULL);srand(tpstart.tv_usec);//通过使用微妙，来增加随机数的随机性iRet = (1+(int)(300.0*rand()/(RAND_MAX+1.0)));//产生1到RAND_MAX之间的整数return iRet;}int main(int argc,char *argv[]){int iTime,iValue;for(iTime=0 ;iTime<10 ;iTime++ ){iValue = MyRand();printf("iTime%d = %d \n",(iTime+1),iValue);sleep(1);}printf("RAND_MAX = %d \n",RAND_MAX);return 0;}
/************************************************************* FileName : rand.c FileFunc : 产生随机长整型正整数 Version : V0.1 Author : Sunrier Date : 2012-05-11 Descp : Linux下产生长整型正整数 *************************************************************/#include <stdio.h>#include <stdlib.h>#include <sys/timeb.h>#include <math.h>long LongRand( void ){struct timeb tp;unsigned short time_seed[3];long lRet;ftime(&tp);time_seed[0]=tp.millitm * tp.millitm;time_seed[1]=tp.millitm;time_seed[2]=tp.time/tp.millitm;lRet=jrand48(time_seed);return fabs(lRet);}int main(int argc,char *argv[]){int iTime;long lValue;for(iTime=0 ;iTime<10 ;iTime++ ){lValue = LongRand();printf("iTime%d = %d \n",(iTime+1),lValue);sleep(1);}return 0;}
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