C C++编程产生指定范围内的随机数

谁践踏了优雅 2022-05-19 07:11 289阅读 0赞

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。