Write the definition for a void function called to_screen. The function to_screen has one formal parameter called file_stream, which is of type ifstream. The precondition and postcondition for the function are as follows: //Precondition: The stream file_stream has been connected //to a file with a call to the member function open. The //file contains a list of integers (and nothing else). //Postcondition: The numbers in the file connected to //file_stream have been written to the screen one per line. //(This function does not close the file.)

To work with file input streams, we first need to include the necessary header files: ```cpp #include #include ``` `iostream` is required for standard input/output functions, and `fstream` is required for file input/output functions.

Based on the problem requirements, define the `to_screen` function with the parameter. Note that we use 'ifstream&' since we are passing the file_stream by reference. ```cpp void to_screen(std::ifstream& file_stream){ // Read integers from the file and print them to the screen } ```

Inside the function, use a while loop to read integers from the file connected to `file_stream` and print them on the screen one per line. ```cpp void to_screen(std::ifstream& file_stream){ int number; while (file_stream >> number) { std::cout << number << std::endl; } } ``` In the while loop, the extraction operator (>>) reads an integer from `file_stream` and stores it in the variable `number`. The loop continues until the end of the file or an error occurs during the extraction (e.g., when trying to read something other than an integer). Inside the loop, the numbers are printed to the screen using std::cout, and 'std::endl' is used to output a newline after each integer. The function is now complete and adheres to the given preconditions and postconditions.