shuffle.cpp

#include <iostream>
#include <vector>
#include <vector>

using namespace std;

void pushAll(std::vector<char> &sec, char begin, char end) {
	for (char x = begin; x <= end; ++x)
		sec.push_back(x);
}

int main() {
	std::vector<char> chars;
	pushAll(chars, 'a', 'z');
	pushAll(chars, 'A', 'Z');
	pushAll(chars, '0', '9');

	for (char c : chars) {
		cout << c ;
	}
	cout << endl;
	
	for (size_t i = 0; i < chars.size(); ++i) {
		const size_t rand = 12345678 * i + 23456789;
		const size_t j = i + rand % (chars.size() - i);
		if (i != j)  // just to be careful
			std::swap(chars[i], chars[j]);
	}

	for (char c : chars) {
		cout << c ;
	}
	cout << endl;

	for (size_t i0 = 0; i0 < chars.size(); ++i0) {
		const size_t i = chars.size() - i0 - 1;
		const size_t rand = 12345678 * i + 23456789;
		const size_t j = i + rand % (chars.size() - i);
		if (i != j)  // just to be careful
			std::swap(chars[i], chars[j]);
	}

	for (char c : chars) {
		cout << c ;
	}
	cout << endl;

	return 0;
}