Question

Give a definition for the function with the following function declaration. The class BankAccount is defined in Display 10.5 double difference(BankAccount account1, BankAccount account2); / / Precondition: account1 and account2 have been given values // (that is, their member variables have been given values). // Returns the balance in account1 minus the balance in account2.

Short answer

Question: Define a function called 'difference' that takes two BankAccount objects as arguments and returns the difference in their balances. Answer: The 'difference' function can be defined as follows: ```cpp double difference(BankAccount account1, BankAccount account2) { double balance1 = account1.get_balance(); double balance2 = account2.get_balance(); double difference_value = balance1 - balance2; return difference_value; } ```

Step-by-step solution

Function Declaration

First, we need to write the function declaration, which is already provided. Copy the following function declaration to start our function definition: ``` double difference(BankAccount account1, BankAccount account2); ```

Accessing BankAccount Balances

Now, we want to access the balance of each BankAccount object. Let's assume there is a public member function in BankAccount class called 'get_balance()', which returns the balance of the account. We can access the balance of both accounts as follows: ``` double balance1 = account1.get_balance(); double balance2 = account2.get_balance(); ```

Calculate Difference

To calculate the difference between the two account balances, subtract balance2 from balance1: ``` double difference_value = balance1 - balance2; ```

Return the Result

Finally, return the calculated difference as the function output: ``` return difference_value; ```

Complete Function Definition

Now we can combine the steps to form the complete function definition: ```cpp double difference(BankAccount account1, BankAccount account2) { double balance1 = account1.get_balance(); double balance2 = account2.get_balance(); double difference_value = balance1 - balance2; return difference_value; } ```