If you need a function to get both the number of items and the cost per item from a user, which would be a good function declaration to use? void getData(int count, float cost); int getData(float cost); int,float getData( ); void getData(int\&; count, float\&; cost);

The best function declaration for obtaining both the number of items and the cost per item from a user is: ```cpp void getData(int& count, float& cost); ``` ### Explanation: 1. **Pass by Reference (`int& count, float& cost`):** - **Purpose:** By passing parameters by reference, the function can modify the original variables provided by the caller. This is essential when you want the function to "return" multiple values. - **Usage:** Inside the `getData` function, you can directly assign values to `count` and `cost`, and these changes will be reflected outside the function. 2. **`void` Return Type:** - **Reasoning:** Since the function's primary purpose is to modify the input parameters, it doesn't need to return any value. Using `void` makes this intention clear. ### Why Other Options Are Less Suitable: 1. **`void getData(int count, float cost);`** - **Issue:** Parameters are passed by value, meaning the function works with copies. Changes to `count` and `cost` inside the function won't affect the original variables. 2. **`int getData(float cost);`** - **Issue:** This declaration only allows for one parameter and returns an `int`, which doesn't align with the requirement to obtain both `count` and `cost`. 3. **`int, float getData();`** - **Issue:** This is not valid syntax in C++. A function cannot return multiple values directly in this manner. ### Example Implementation: ```cpp #include void getData(int& count, float& cost) { std::cout << "Enter the number of items: "; std::cin >> count; std::cout << "Enter the cost per item: "; std::cin >> cost; } int main() { int itemCount; float itemCost; getData(itemCount, itemCost); std::cout << "You entered " << itemCount << " items at $" << itemCost << " each.\n"; return 0; } ``` In this example, `getData` successfully modifies `itemCount` and `itemCost` based on user input, demonstrating the effectiveness of passing parameters by reference. **Answer:** Use a void function with reference parameters, such as  void getData(int& count, float& cost);