> For the complete documentation index, see [llms.txt](https://fusee.gitbook.io/mx-sdk-as/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://fusee.gitbook.io/mx-sdk-as/the-flip-smart-contract/the-flip-smart-contract-part-7-make-the-flip.md).

# The Flip Smart Contract part 7 : Make the flip

Flips are initialised, time to make them

Remember, we built an endpoint that allow players to make a bet, but it's result should be computed in another transaction.

We said earlier that the bounty endpoint, not built yet, will compute all waiting bets results in a row. We'll write the bounty endpoint in the next part of this tutorial, now we'll focus on writing the function to generate result for a single bet.

## Function's signature

Here is the function's signature, again inside the `FlipContract` class : 

```typescript
private makeFlip(
    bountyAddress: ManagedAddress,
    flip: Flip
): void {
    // Function code goes here
}
```

The key point is the `private` keyword. `makeFlip` is NOT an endpoint but an internal function we'll use in the future bounty endpoint.

`bountyAddress` is the address of the bounty caller endpoint. It is needed to send the incentive.

{% hint style="danger" %}
Making a function `private` ensure no one will be able to call it, forget it is a big security issue.
{% endhint %}

### Function's body

Here is the full function : 

```typescript
private makeFlip(
    bountyAddress: ManagedAddress,
    flip: Flip
): void {
    const randomNumber = RandomnessSource.nextU8InRange(ManagedU8.fromValue(0), ManagedU8.fromValue(2))
    const isWin = randomNumber == ManagedU8.fromValue(1)

    this.send
        .direct(
            bountyAddress,
            flip.tokenIdentifier,
            flip.tokenNonce,
            flip.bounty
        )

    const profitIfWin = flip.amount * BigUint.fromU64(2)

    if (isWin) {
        this.send
            .direct(
                flip.playerAddress,
                flip.tokenIdentifier,
                flip.tokenNonce,
                profitIfWin
            )
    } else {
        let oldTokenReserve = this.tokenReserve(
            flip.tokenIdentifier,
            flip.tokenNonce
        ).get()

        this.tokenReserve(
            flip.tokenIdentifier,
            flip.tokenNonce
        ).set(oldTokenReserve + profitIfWin)
    }

    this.flipForId(flip.id).clear()
}
```

Nothing special in this function.

{% hint style="info" %}
`RandomnessSource` is a class containing statics methods allowing you to generate random numbers. Remember that these numbers are predictables knowing current block random seed and transaction infos (sender, hash, ...).
{% endhint %}

## Next up

The contract is almost finished, last thing we need to do is the bounty endpoint.