如何生成在某个区间的随机数

一，需要的库函数和头文件

#include <stdlib.h>

int rand(void);

void srand(unsigned int seed);



二，函数说明

The rand() function returns a pseudo-random integer between 0 and RAND_MAX.



The srand() function sets its argument as the seed for a new sequence of pseudo-random integers to be returned by rand(). These sequences are repeatable by calling srand() with the same seed value.

If no seed value is provided, the rand() function is automatically seeded with a value of 1.

简单的说rand函数生成一个范围从0到RAND_MAX的随机数，srand是设置随机生成器的种子。



三，使用方法

要求生成一个从区间intBeg到intEnd范围的随机数。



//以当前系统时间作为种子

srand((unsigned int) time(0));



//生成随机数

int randval = intBeg+(int) ((float)(intEnd-intBeg)*rand()/(RAND_MAX+1.0));