C/C++编程产生指定范围内的随机数，直接上个小程序：

#include #include #include #include #include  

/* * 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。