---
#### Repository
e.g. https://github.com/steemit/steem-js
#### What Will I Learn?
- Create Gambling Game Script
#### Requirements
- Node.JS, [Here](https://nodejs.org/en/)
- Steem Package (Install: npm install steem --save)
#### Difficulty
- Intermediate
#### Tutorial Contents
You will learn how to create gambling game that works with SBD
#### Curriculum
- [Bot Build #1](https://utopian.io/utopian-io/@lonelywolf/build-bot-using-steem-js-1-upvoting-bot-by-friend-list-or-by-trending-posts)
- [Bot Build #2](https://utopian.io/utopian-io/@lonelywolf/bot-build-2-auto-follow-bot)
- [Bot Build #3](https://utopian.io/utopian-io/@lonelywolf/bot-build-3-auto-reward-claimer)
- [Bot Build #4](https://steemit.com/utopian-io/@lonelywolf/bot-build-4-resteem-bot-with-friend-list)
- [Bot Build #5](https://steemit.com/utopian-io/@lonelywolf/bot-build-5-curation-trail)
- [Bot Build #6](https://steemit.com/utopian-io/@lonelywolf/bot-build-6-simple-paid-upvoting-bot)
- [SteemJS Tutorials #1](https://utopian.io/utopian-io/@lonelywolf/steem-js-tutorials-1-basics-validating-wif-key)
- [NodeJS Tutorials #1](https://utopian.io/utopian-io/@lonelywolf/nodejs-tutorials-1-creating-a-static-site-node-js)
#### The Tutorial
### Step 1 - Setup, Variables & Functions
, first of all, we need some variables and functions to set up the base.
so we need a `percentage`, this number will give us the win percentage
we need account name & key `Important`: At this time you will need to use WIF Active Key, so the `guest123` account not going to help you, you can make your own repl.it or nodejs script and put your account and active key!
and we need the minimum gambling amount
```
const percentage = 50; //If Higher Than This Number, Win.
const ACC_NAME = 'guest123', //Account Name
ACC_KEY = '5JRaypasxMx1L97ZUX7YuC5Psb5EAbF821kkAGtBj7xCJFQcbLg', //Account WIF (Active Key Only Work On This Script)
MINIMUM_AMOUNT = 0.01; // Minimum Gamble Amount
```
so just to give it some `Life` we can add some comments when the script starts
```
console.log("Gambling Game Script Running...");
setTimeout(function(){console.log("Waiting For Transfers...");}, 1000);
```
to get the better performance we can connect to a custom WebSocket.
```
steem.api.setOptions({ url: 'wss://rpc.buildteam.io' }); // Custom Websocket.
```
You can stay with the default and not change it.
now we need 2 functions, one - the gamble function and second - transfer function
at the gamble function, we will need the gamble account name and the amount of the gamble
```
function Gamble(Gambler, Amount){
}
```
at the transfer function, we will need account name, memo and amount to send
```
function SendTransfer(Name, Memo, Amount){
}
```
### Step 2 - Create The Functions
let's go from the easier to the harder and start with the transfer function.
because the transfer function need a full `name` of the amount we need to send `0.001 SBD` and not `0.001`
```
Amount = Amount.toString() + " SBD";
```
We're changing the integer (Amount) to a string and add the ` SBD` to the amount.
and now we just need to send the transfer
```
steem.broadcast.transfer(ACC_KEY, ACC_NAME, Name, Amount, Memo, function(err, result) { //Send Transfer
console.log(err, "Sent " + Amount + " To " + Name + " With The Memo: " + Memo);
```
`ACC_KEY` - [Important] The Active Private Key
`ACC_NAME` - The Sender(You) Account Name
`Name` - The Reciever Account Name
`Amount` - The SBD Amount (The Amount Variable)
`Memo` - The Message (MEMO)
and we send console comment so we can know that we sent the transfer.
And, Here we're done with the transfer function, really simple yea?
let's go to the actual gamble.
first, we need a random number between 1 to 100
```
const rand = Math.floor(Math.random() * 100) + 1; //Random Number between 1 to 100
```
this number is the winner / looser number.
now we need to check if the random number is higher than our percentage.
```
if(rand > percentage){ //Checking if the random number is higher than our percentage
let WinnerAmount;
if(Amount > 0.01){
WinnerAmount = Amount*1.95;
}else{
WinnerAmount = Amount*2; //if the amount is less than 0.01 it will double the win amount because you can't send 0.00195.
}
SendTransfer(Gambler, "You Won This Round! Number: " + rand +", Your Gamble - " + Amount + " SBD, You Earned Totally: " + Amount*0.95 + " SBD. Come Back Anytime!", WinnerAmount);
console.log("Gambler " + Gambler + " Won!");
}else{
SendTransfer(Gambler, ":(, You Lose This Round, Your Number: " + rand + ", Best Of Luck Next Time!", 0.001);
console.log("Gambler " + Gambler + " Lost!");
}
```
at first, we check if the random number is higher than the percentage if it is we creating `WinnerAmount` variable (empty) and check if the gambling amount is higher than 0.01 if it is we can double it by 1.95 (because we need to earn something - 5%)
if it's not we want to double it by 2 because we can't send higher than 3 digit number (example: 0.00195)
`Note`: this will work only if you down the minimum number
now we just need to send the transfer with a message/memo that he wins and how much he actually earn, for example, if he sends 0.01 he earn 0.0095.
and again we send a comment to the console so we can know if someone wins
now if the gambler lost we send transfer with message/memo that he loose with 0.001 (Amount)
and again we send a comment to the console.
**Here we done with the functions, now we just need to "listen"/get transfers and run the function**
### Step 3 - Read Transfers And Make The Gamble
first of all, like the latest tutorials we want to listen for transfer/transaction
```
steem.api.streamTransactions('head', function(err, result) { //Streaming The latest Transactions That Goes Through The Steem Blockchain
}
```
this function receives any transaction that goes through the steem blockchain, and the transfers we need to get.
now we need 2 variables, one is the type of the transaction and the second is the data that we get with the transaction.
```
let type = result.operations[0][0]; // transaction type
let data = result.operations[0][1]; // transaction data
```
we need to check if the type is transfer and if the receiver is our account.
```
if(type == 'transfer' && data.to == ACC_NAME){ // Checking if transaction type is `transfer` and check if the reciever is our accout.
}
```
now because I want the gambles only as SBD gamble we will get every STEEM as a donation, we need to check if the amount is a STEEM token.
```
if(data.amount.split(' ')[1] == "STEEM"){ // Checking The Token Type
SendTransfer(data.from, "Thanks for you donation, we really appreciate that. if this is not a donation please contact us!", 0.001);
console.log("Donation From " + data.from + ", " + data.amount);
}
```
if it is we send a "thank you" message and sending a comment to the console.
now we need to check if the amount is in SBD balance and start the gamble.
```
else{
if(data.memo == "Gamble"){ //Checking If The Transfer Is For Gamble
if(data.amount.split(' ')[0] < MINIMUM_AMOUNT){ // Checking If The Amount Is Below The Minimum Amount
console.log("Wrong Gamble, reason: below the minimum.");
SendTransfer(data.from, "Your Gamble Amount Is Less Than The Minimum, The Minimum Is " + MINIMUM_AMOUNT + " SBD", data.amount);
}else{
console.log("Incoming Gamble From " + data.from);
Gamble(data.from, data.amount.split(' ')[0]);
}
}
}
```
first to know that is a gamble we want to check if the sender actually wants to gamble, so we check if the memo is `Gamble`.
if it is we check if the Amount is higher than the minimum.
if it's not we send a comment to the console and sending back the amount to the sender with a message that the amount is less than our minimum.
if the amount is higher than the minimum we send a comment to the console and start the gamble.
from here the functions make the rest.
And, we're done with the script.
it's little long but it's really cool script.
`Note`: this script tested on my own server with my user and it's work perfect
SteemD proofs:
the 2 in the middle is an example of a bad test.
**You can check the full work at my repl.it account and other bots that I create!**
#### Proof of Work Done
the work made in Repl.it, https://repl.it/@lonelywolf22/Steem-Bots-Gambling-game-V01-Done
user: https://repl.it/@lonelywolf22
GitHub: https://github.com/lonelywolf1
Utopian Tutorials GitHub Repository: https://github.com/lonelywolf1/Bot-Projects-SteemJS