C C++编程产生指定范围内的随机数

C/C++编程产生指定范围内的随机数，直接上个小程序：

#include <stdlib.h>
#include <time.h>
#include <stdio.h>
#include <string>
#include <string.h>

/*
 * 获取随机数
 * return :  随机数
 */
int commonGetRandNumber(const int low, const int high)
{
    int randNum = 0;

    //生成随机数
    randNum = rand() % (high - low + 1) + low;

    return randNum;
}

#define RAND_MAX_LEN     (16)
#define RAND_MIN_VALUE   (0)
#define RAND_MAX_VALUE   (9999)

/*
 * 获取随机数的字符串形式
 * return :  随机数字符串
 */
std::string commonGetRandString()
{
    int low     = RAND_MIN_VALUE;
    int high    = RAND_MAX_VALUE;
    int randNum = 0;
    char randArray[RAND_MAX_LEN] = {0};
    std::string randStr;

    //生成随机数
    srand(time(0));
    randNum = commonGetRandNumber(low, high);

    snprintf(randArray, sizeof(randArray)-1, "%d", randNum);

    randStr = randArray;

    return randStr;
}

/*
 * 获取根据给定字符数组和随机数生成随机字符串
 */
std::string getNonceStr(int length = 32)
{
    std::string chars = "abcdefghijklmnopqrstuvwxyz0123456789";
    std::string str   = "";

    //生成随机数
    srand(time(0));
    for ( int i = 0; i < length; i++ )
    {
        str += chars.substr(commonGetRandNumber(0, chars.size() - 1), 1);
    }

    return str;
}


int main()
{

    //获取随机数
    srand(time(0));
    int randNum = commonGetRandNumber(10, 100);
    printf("randNum=%d\n", randNum);
    
    //获取随机数的字符串形式
    std::string randStr = commonGetRandString();
    printf("randStr=%s\n", randStr.c_str());
    
    //获取根据给定字符数组和随机数生成随机字符串
    std::string randChar = getNonceStr();
    printf("randChar=%s\n", randChar.c_str());

}

调用rand()会产生[0,32757]之间的随机数，(high - low)的绝对值不能超过32767。