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。
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