Random number generator

Not to be confused with User:XKCD Random Number.

A random number generator (a.k.a RNG) generates a number randomly, usually within some range or subset. It is as the name implies. Not to be confused with the program in XKCD's 221st page.

This system is often used by "Guessing number".

Python

from random import *
a = input("Please Input how many life do you have(If you guessing wrong, your life will be leaves 1): ")
if a == '':
    a = 10
elif a == 'H':
    a = 1
a = int(a)
answer = randint(-50, 50)
# randint(X, Y) generates a random integer from X to Y.
while a > 0:
    b = input("Please Input what number are you guessing: ")
    b = int(b)
    if b == answer:
        print("That's it! Thanks for playing!")
        break
    elif b > answer:
        a -= 1
        print(f"{b} is too big! Try again({a} lifes left): ")
    elif b < answer:
        a -= 1
        print(f"{b} is too small! Try again({a} lifes left): ")

C++

#include<bits/advc++.h>
using namespace std;
int a, b;
string com;
int main()
{
    srand((unsigned long)time(NULL));
    // When you wanna use rand() function, you must use srand(unsigned long int) to generate a seed.
    cout<<"Boot manager"<<endl
        <<"1. Normally boot"<<endl
        <<"2. Weirdly boot"<<endl
        <<"3. Exit"<<endl;
    cin>>a;
    switch (a)
    {
        case 1:
        {
            system("cls");
            print("\n\n\n\n\n\n\n\n\n\nLoading Operating System...");
            Sleep(5000);
            break;
        }
        case 2:
        {
            system("cls");
            print("\n\n\n\n\n\n\n\n\n\nLoading Operating System...");
            Sleep(5000);
            for(int i=1;i<=100;i++)
            {
                for(int j=1;j<=100;j++)
                {
                    cout<<(char)(rand()%127);
                }
                cout<<"\n"<<endl;
            }
            Sleep(5000);
            system("cls");
            break;
        }
        case 3:
        {
            print("Exiting...");
            Sleep(2000);
            system("cls");
            return 0;
        }
    }
    system("cls");
    system("color 1f");
    cout<<"Are you sure to go into OS?"<<endl;
    cin>>b;
    if(b==0)
    {
        system("cls");
        cout<<"(ノ｀Д)ノF*ck you"<<endl;
        Sleep(2000);
        system("cls");
        return 0;
    }
    system("cls");
    cout<<"Genshin Impact(Not) DOS, start!!!!!!!!!!!!!"<<endl;
    for(int i=1;i<=20;i++)
    {
        cout<<"_";
        Sleep((rand()%1000)+1);
        /* Sleep(int X) function is from windows.h library. It pauses program for X milliseconds.
         * rand(void) function generates a random number from 0 to 2147483647.
         */
    }
    system("cls");
    cout<<"MS-DOS 12.3.3222 Windows-based startuping......"<<endl;
    Sleep(1000);
    system("cls");
    for(int i=1;i<=100;i++)
    {
        for(int j=1;j<=100;j++)
        {
            cout<<(char)(rand()%127);
            // Here generates some random ASCII character.
        }
        cout<<"\n"<<endl;
    }
    Sleep(2000);
    system("cls");
    system("color 0f");
    system("pause");
    system("cls");
    print("Hello, DOS!\n");
    print("This OS is based on Microsoft Windows, is a simulator.\n");
    Sleep(2000);
    system("cls");
    while(true)
    {
        cout<<">>>";
        getline(cin, com);
        system(com.c_str());
        puts("\n\n");
    }
}