Random number generator

Not to be confused with 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.

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");
    }
}