Casino Blackjack aka Twenty-one (Written in C++; I used Visual Studio but many compilers are supported

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Fun old-school CMD console Blackjack game written in C++ as a school projects from many moons ago..

This is a legacy / educational project – not production-grade casino software. It’s here as a snapshot of where my C++ journey started.

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#This is Blackjack, written in C++. Includes:
-User accounts (Includes tally of winnings and player rankings)
-Leaderboard
-Basic dealer AI (very basic lol but met criteria for project) / Level of difficulty
-Lots of other stuff that I will add

Main Code:

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Youtube Demo of Game

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What You Get

• Blackjack game loop
  • Hit / Stand
  • Double Down (when initial total is 9, 10, or 11)
  • Insurance side bets when dealer shows an Ace
• 1–7 players (local hotseat)
  • Solo: you vs dealer
  • Multi: multiple human players taking turns at the same console
• Persistent user accounts
  • Simple User class: name, email, username, pw, earnings, rank
  • Accounts stored in userDB.txt between runs
• Dealer difficulty levels
  • Beginner – dealer stands on soft 17
  • Expert – dealer hits on soft 17 (When the dealer hits on soft 17, it gives them a chance to improve their hand but it also adds risk of busting; aka Expert can improve on soft 17; Beginner plays it safe)
• Leaderboard
  • Players ranked by total lifetime earnings
  • Custom selection sort over the User array

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Game Rules & Payouts

The project follows standard, simplified Blackjack rules:

• Card values
  • Number cards: face value
  • J, Q, K: 10 points
  • A: 1 or 11 points (player chooses; dealer logic adjusts)
• Blackjack
  • Natural blackjack pays 3:2 (150% of your bet in profit)
• Standard outcomes
  • Win: you beat dealer without busting ⇒ you win an amount equal to your bet
  • Push: same total as dealer ⇒ your bet is returned
  • Loss: you bust or dealer is closer to 21 ⇒ you lose your bet
• Insurance
  • Offered if dealer’s face-up card is an Ace
  • You can bet up to half your original bet that the dealer has blackjack
  • Insurance pays 2:1 if the dealer does have blackjack

All players start each session with an initial bankroll of $50, and that bankroll is tracked per account across runs.

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Project Layout

The repo is intentionally small:

• Blackjack/Blackjack/main.cpp
  Core of the program:

  • User auth / signup (userSignIn)
  • Game loop (playFirstHand)
  • Betting, insurance, and double-down logic
  • Dealer AI (hitUntilStandAI, checkSoftOrHardAI)
  • Hand evaluation (CardValue, getHandValue)
  • Leaderboard and ranking (determineRank, selectionSort, displayResults)
  • File I/O for user accounts (loadAccounts, updateDB, updateEarnings)

• Blackjack/Blackjack/User.h
  Simple User class with public fields:

  • string name
  • string email
  • string username
  • string pw
  • double earnings
  • int rank

• userDB.txt (created/updated at runtime)

  • Flat-file “database” containing:
    • Number of users
    • One block per user: name, email, username, password, earnings, rank

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Tech Stack & Constraints

• Language: C++ (written against a 2016-era toolchain)
• Standard library:
  • <iostream>, <iomanip>, <string>, <fstream>
  • <algorithm> (uses random_shuffle in this repo version)
  • <cstdlib>, <ctime>, <limits>
• OS assumptions: Windows
  • Uses system("cls") to clear the console
  • Uses system("pause") for “press any key to continue”
  • On Linux/macOS you’ll either need to stub these out or replace them

V2 Updates / Shuffling

The latest version in this repo uses Mersenne Twister 19937 generator (mt19937 algo)
Previously I used the system time thinking that was random... which it is if you wait hours in between each round lolz. The demo video I made years ago where somehow me and the dealer got face cards twice in a row (and the odds of that happening) bothered me even though the teacher gave me an A since he prob didn't read the code just saw it worked - Anywho; not that it matters now unless I wanna start writing massive apps that need C++ but I felt like I should archive this if I didn't at least fix that part. That's my story ;) - Anyways enjoy :

void shuffleDeck(int deck[], int size)
{
    random_device rd;
    mt19937 g(rd());
    std::shuffle(deck, deck + size, g);  // Explicit std:: for clarity
}
/>