## Introduction to the exchange function We're going to take a walk-through of the *exchange* function in the *StableSwap* pool. ### Exchange Function Walk-through The *exchange* function has the following steps: 1. **Normalizes token balances (memory)** This is the first thing the function does. It makes sure all token balances have 18 decimals, regardless of the actual token's decimal places. 2. **Transfer token in (memory)** The *exchange* function will then transfer the token *in* to the pool. 3. **Update token in balance (memory)** The normalized balance of the token *in* is stored in memory. 4. **Calculate token out balance** * **Calculate A** * **Calculate D** The function will calculate the new balance of the token *out*. 5. **Calculate token out** The difference between the new token *out* balance and the old token *out* balance is calculated. 6. **Calculate swap fee** The *exchange* function calculates the swap fee which is taken out of the token *out*. 7. **Update token balances (storage)** This step updates the token balances in storage to reflect the changes. 8. **Transfer token out** Finally, the *exchange* function transfers the token *out* to the user. This walk-through provides a basic understanding of the *exchange* function.