C++编程产生指定范围内的随机数

#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()); }