Filling a string with random characters

#include <iostream> #include <sstream> #include <stdlib.h> using namespace std; const char * ar[] = {"а", "б", "в", "г", "д", "е", "ё", "ж", "з", "и", "й", "к", "л", "м", "н", "о", "п", "р", "с", "т", "у", "ф", "х", "ц", "ч", "ш", "щ", "ъ", "ы", "ь", "э", "ю", "я"}; int main(int argc, char* argv[]) { int n; string s = ""; stringstream ss (argv[1]); ss >> n; for(int i=0; i < n; i++) s += ar[rand() % (sizeof ar/sizeof (char *))]; cout << s << endl; return 0; } 

UPD Corrected by the recommendation of @GLmonster

There is such a table of ANSI characters, which can be seen here as an example of a table .

Each character has its own code from 0 to 255. And the Russian letters (large and small) fall from 192 to 255, respectively, only large ones from 192 to 223, and only small ones from 224 to 255.

We create an array of char type, fill it with Russian characters and, as a result, print the characters on the screen using a random index of our array :)

You can also just make an array of type int and fill it with character codes, and when output, put (char), the result will be the same.

For random output, you need to connect time.h, you can implement randomness in a certain range using the following rand ()% algorithm (MAXIMUM - MINIMUM + 1) + MINIMUM.

In the end, here:

 #include <iostream> #include <time.h> // макрос, который выводит случайные числа в определенном диапазоне // rand() % (МАКСИМАЛЬНОЕ - МИНИМАЛЬНОЕ + 1) + МИНИМАЛЬНОЕ #define _rand(min, max) ( rand() % ((max) - (min) + 1) + (min) ) int main(int argc, char** argv) { setlocale(LC_ALL, "russian"); srand(time(NULL)); char chars[32]; // наш алфавит // заполняем массив for(int i=224, n=0; i<=255; ++i, ++n) { chars[n] = (char) i; // (char) приводит код к символу } // выводим собранный массив std::cout << "Собранный массив:\n"; for(int i=0; i<32; ++i) { std::cout << chars[i] << "\t"; } // выводим собранный массив в случайном порядке std::cout << "\nСлучайным образом:\n"; for(int i=0; i<100; ++i) { std::cout << chars[_rand(0, 31)] << "\t"; } std::cout << std::endl; return 0; } 

@skies , you wrote a bunch of tips in the answers and comments (there are better and worse).

I think that if you need a simple program, then it will be platform-specific (that is, you know the Russian encoding (at least one-byte, UTF-8 or Unicode) in your system and write for it. You can clarify in the question for which OS You want the program and get specific advice.

In any case, you need an array of small Russian letters. For a simple program, this is most likely an array of pointers to single-letter strings (strings in C terms, not C ++) (for utf-8 (as in the @alexlz answer)) the string will have 3 bytes (including the terminating '\ 0 '). With this solution, you will use the same algorithm for outputting / inserting Russian letters, regardless of the encoding.

In a program that is as independent as possible of the system (Windows, Mac, * nix, (localization is configured / not configured) and the compiler), inside the program it is probably most convenient to use an array of type int with Unicode. Before output, you will have to (dynamically) determine the current encoding of the Russian language and recode Unicode into it (this is necessary for working with non-military localization).

The approach is not generally accepted, because it is quite complicated. Unfortunately, it is not always possible to do this correctly. For example, a Ubuntu user works in utf-8, but in a particular window gnome-terminal can be set, say, the cp-1251 encoding (this leaves LANG = ru_RU.utf8).

Here is a cross-platform code

 #include <iostream> #include <cstdlib> #include <ctime> #include <locale> #include <string> using namespace std; #ifdef WIN32 #define RUSLOCAL "rus" #elif __unix #define RUSLOCAL "ru_RU.utf-8" #endif wchar_t randomletter() { static bool seedset = false; if (!seedset) { srand(static_cast<unsigned> (time(NULL))); seedset = true; } static wchar_t alph[] = L"абвгдеёжзиклмнопрстуфхцчшщьыъэюя"; return alph [rand() % (sizeof(alph) / sizeof (alph[0]) - 1)]; } int main(int argc, char* argv[]) { locale::global (locale( RUSLOCAL )); for (int i = 0; i<10; i++) { wcout << randomletter() << L" "; } wcout << endl; #ifdef WIN32 system ("PAUSE"); #endif return 0; } 

Tested in Linux g ++ and in Windows VC ++ 2010. If precompiled headers are used in Windows, you must also include stdafx.h.

Arrays are not needed for random letters: 'a' + rand ()% 33

In pseudocode, the algorithm for filling an array with random small Russian letters will be the following:

1 . We generate random number of RANDcode in the range of MINcode to MAXcode. Here MINcode is the minimum code for a Russian small letter, and MAXcode is the maximum code for a small Russian letter, respectively.

2 Fill the array with the number of RANDcode.

3 If the array is not yet full, then go to step 1.

To generate a random number in the range from MINcode to MAXcode, you can use the iRand function (see the article “ Generating a Random Number in the Required Range ”). It remains to determine only the values ​​of MINcode and MAXcode - they depend on the encoding. For example, if KOI-8R encoding is used, then MINcode = 0xC0, MAXcode = 0xDF; and if the encoding is CP1251 , then MINcode = 0xE0, MAXcode = 0xFF.

In general, if you do not need to bother with the encoding, then you first need to prepare the array ALLRUSSMALLLETTERS, which will list all the small Russian letters, and generate a random number for the index of this array (from 0 to sizeof (ALLRUSSMALLLETTERS) -1). For a random index from the ALLRUSSMALLLETTERS array, you need to take a character and insert it into the array to be filled.

1. set manually the required character set (array)
2. get its size
3. create a function returning a random character (random from a range of characters)

version with locales, etc. not worth it, is in itself a task. Cross-platform in this case is maintained. If suddenly, the console will give out krakozabli - we kick the console or user. For example, before calling in Windows from cmd, you can set a locale. If there is no locale in it, let the user think about it. Something like this, the code options have already been given a lot.