> For the complete documentation index, see [llms.txt](https://tucana-1.gitbook.io/tucana-developer-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://tucana-1.gitbook.io/tucana-developer-docs/spot-dex/spot-contract/feature-available/swap-and-calculate-swap-result.md).

# Swap and Calculate Swap Result

## 1. Swap

### 1.1. Function params

* **account**: the signer of the user.
* **pool**: the object of the pool.
* **a\_to\_b**: the swap direction, a2b equals ***true*** means sold coin a then get coin b.
* **by\_amount\_in**: when it equal ***true*** means want to fix the amount of input coin. when it equal ***false*** means want to fix the amount of output coin.
* **amount**: when by\_amount\_in equals ***true***, amount means the quantity of input coin, when by\_amount\_in equals ***false***, amount means the quantity of output coin.
* **amount\_limit**: the threshold value of coin. when by\_amount\_in equals ***true***, it means the minimum amount about received coin, when by\_amount\_in equals ***false***, it means the maximum amount abount sold.
* **sqrt\_price\_limit**: two constant of sqrt price(x64 fixed-point number). When a2b equals ***true***, it equals 4295048016, when a2b equals ***false***, it equals 79226673515401279992447579055.

### 1.2. Function

```rust
// tucana_clmm::router
public entry fun swap(
    account: &signer,
    pool: Object<Pool>,
    a_to_b: bool,
    by_amount_in: bool,
    amount: u64,
    amount_limit: u64,
    sqrt_price_limit: u128,
) {
    ...
}

```

## 2. Swap with partner&#x20;

### 2.1 Function params

* **account**: the signer of the user.
* **pool**: the object of the pool.
* **partner**: the object of the partner, if you want to create, then connect manager.
* **a\_to\_b**: the swap direction, a2b equals ***true*** means sold coin a then get coin b.
* **by\_amount\_in**: when it equal ***true*** means want to fix the amount of input coin. when it equal ***false*** means want to fix the amount of output coin.
* **amount**: when by\_amount\_in equals ***true***, amount means the quantity of input coin, when by\_amount\_in equals ***false***, amount means the quantity of output coin.
* **amount\_limit**: the threshold value of coin. when by\_amount\_in equals ***true***, it means the minimum amount about received coin, when by\_amount\_in equals ***false***, it means the maximum amount abount sold.
* **sqrt\_price\_limit**: two constant of sqrt price(x64 fixed-point number). When a2b equals ***true***, it equals 4295048016, when a2b equals ***false***, it equals 79226673515401279992447579055.

### 2.2 Function

```rust
// tucana_clmm::router
public entry fun swap_with_partner(
    account: &signer,
    pool: Object<Pool>,
    partner: Object<Partner>,
    a_to_b: bool,
    by_amount_in: bool,
    amount: u64,
    amount_limit: u64,
    sqrt_price_limit: u128,
) {
    ...
}
```

## 3. Calculate swap result

### 2.1 View function params

* **pool**: the object of the pool.
* **a\_to\_b**: the swap direction, a2b equals ***true*** means sold coin a then get coin b.
* **by\_amount\_in**: when it equal ***true*** means want to fix the amount of input coin. when it equal ***false*** means want to fix the amount of output coin.
* **amount**: when by\_amount\_in equals ***true***, amount means the quantity of input coin, when by\_amount\_in equals ***false***, amount means the quantity of output coin.

### 2.2 View Function

```rust
// tucana_clmm::router
/// The calculated swap result
struct CalculatedSwapResult has copy, drop, store {
    amount_in: u64,
    amount_out: u64,
    fee_amount: u64,
    fee_rate: u64,
    after_sqrt_price: u128,
    current_sqrt_price: u128,
    is_exceed: bool,
    step_results: vector<SwapStepResult>
}


#[view]
public fun calculate_swap_result(
    pool: Object<Pool>,
    a2b: bool,
    by_amount_in: bool,
    amount: u64,
): CalculatedSwapResult acquires Pool {
    ...
}

```


---

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