問題描述

我正在做一個書本練習(xí)，內(nèi)容是編寫一個生成偽隨機數(shù)的程序.我從簡單開始.

I'm doing a book exercise that says to write a program that generates psuedorandom numbers. I started off simple with.

#include "std_lib_facilities.h"

int randint()
{
    int random = 0;
    random = rand();
    return random;
}

int main()
{
    char input = 0;
    cout << "Press any character and enter to generate a random number." << endl;
    while (cin >> input)
    cout << randint() << endl;
    keep_window_open();
}

我注意到每次程序運行時，都會有相同的隨機"輸出.所以我研究了隨機數(shù)生成器，并決定通過在 randint() 中首先包含它來嘗試播種.

I noticed that each time the program was run, there would be the same "random" output. So I looked into random number generators and decided to try seeding by including this first in randint().

    srand(5355);

它一遍又一遍地生成相同的數(shù)字(我現(xiàn)在覺得實現(xiàn)它很愚蠢.)

Which just generated the same number over and over (I feel stupid now for implementing it.)

所以我想我會很聰明并像這樣實現(xiàn)種子.

So I thought I'd be clever and implement the seed like this.

srand(rand());

這基本上和程序最初所做的一樣，但輸出了一組不同的數(shù)字(這是有道理的，因為 rand() 生成的第一個數(shù)字總是 41.)

This basically just did the same as the program did in the first place but outputted a different set of numbers (which makes sense since the first number generated by rand() is always 41.)

我唯一能想到的讓這更隨機的是:

The only thing I could think of to make this more random is to:

1. 讓用戶輸入一個數(shù)字并將其設(shè)置為種子(這很容易實現(xiàn)，但這是最后的手段)或
2. 以某種方式將種子設(shè)置為計算機時鐘或其他不斷變化的數(shù)字.

我是不是腦子進(jìn)水了，我現(xiàn)在應(yīng)該停下來嗎?選項 2 難以實施嗎?還有其他想法嗎?

Am I in over my head and should I stop now? Is option 2 difficult to implement? Any other ideas?

提前致謝.

推薦答案

選項 2 并不難，給你:

Option 2 isn't difficult, here you go:

srand(time(NULL));

你需要為 srand() 包含 stdlib.h 和為 time() 包含 time.h代碼>.

you'll need to include stdlib.h for srand() and time.h for time().

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