我想创建一个随机字符串,由字母-数字字符组成。我希望能够指定字符串的长度。
如何在c++中做到这一点?
我想创建一个随机字符串,由字母-数字字符组成。我希望能够指定字符串的长度。
如何在c++中做到这一点?
当前回答
让我们再次让随机变得方便!
我做了一个很好的c++ 11头解决方案。 您可以轻松地将一个头文件添加到项目中,然后将测试添加到项目中,或者将随机字符串用于其他目的。
这是一个快速的描述,但是您可以通过链接查看完整的代码。解决方案的主要部分是在Randomer类中:
class Randomer {
// random seed by default
std::mt19937 gen_;
std::uniform_int_distribution<size_t> dist_;
public:
/* ... some convenience ctors ... */
Randomer(size_t min, size_t max, unsigned int seed = std::random_device{}())
: gen_{seed}, dist_{min, max} {
}
// if you want predictable numbers
void SetSeed(unsigned int seed) {
gen_.seed(seed);
}
size_t operator()() {
return dist_(gen_);
}
};
随机封装所有随机的东西,你可以很容易地添加自己的功能。有了Randomer之后,生成字符串就很容易了:
std::string GenerateString(size_t len) {
std::string str;
auto rand_char = [](){ return alphabet[randomer()]; };
std::generate_n(std::back_inserter(str), len, rand_char);
return str;
}
在下面写下你的改进建议。 https://gist.github.com/VjGusev/e6da2cb4d4b0b531c1d009cd1f8904ad
其他回答
#include <iostream>
#include <string>
#include <random>
std::string generateRandomId(size_t length = 0)
{
static const std::string allowed_chars {"123456789BCDFGHJKLMNPQRSTVWXZbcdfghjklmnpqrstvwxz"};
static thread_local std::default_random_engine randomEngine(std::random_device{}());
static thread_local std::uniform_int_distribution<int> randomDistribution(0, allowed_chars.size() - 1);
std::string id(length ? length : 32, '\0');
for (std::string::value_type& c : id) {
c = allowed_chars[randomDistribution(randomEngine)];
}
return id;
}
int main()
{
std::cout << generateRandomId() << std::endl;
}
void gen_random(char *s, size_t len) {
for (size_t i = 0; i < len; ++i) {
int randomChar = rand()%(26+26+10);
if (randomChar < 26)
s[i] = 'a' + randomChar;
else if (randomChar < 26+26)
s[i] = 'A' + randomChar - 26;
else
s[i] = '0' + randomChar - 26 - 26;
}
s[len] = 0;
}
Qt使用示例:
QString random_string(int length=32, QString allow_symbols=QString("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")) {
QString result;
qsrand(QTime::currentTime().msec());
for (int i = 0; i < length; ++i) {
result.append(allow_symbols.at(qrand() % (allow_symbols.length())));
}
return result;
}
void strGetRandomAlphaNum(char *sStr, unsigned int iLen)
{
char Syms[] = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
unsigned int Ind = 0;
srand(time(NULL) + rand());
while(Ind < iLen)
{
sStr[Ind++] = Syms[rand()%62];
}
sStr[iLen] = '\0';
}
//C++ Simple Code
#include <bits/stdc++.h>
using namespace std;
int main() {
vector<char> alphanum =
{'0','1','2','3','4',
'5','6','7','8','9',
'A','B','C','D','E','F',
'G','H','I','J','K',
'L','M','N','O','P',
'Q','R','S','T','U',
'V','W','X','Y','Z',
'a','b','c','d','e','f',
'g','h','i','j','k',
'l','m','n','o','p',
'q','r','s','t','u',
'v','w','x','y','z'
};
string s="";
int len=5;
srand(time(0));
for (int i = 0; i <len; i++) {
int t=alphanum.size()-1;
int idx=rand()%t;
s+= alphanum[idx];
}
cout<<s<<" ";
return 0;
}