Question

A car dealer has 10 salespersons. Each salesperson keeps track of the number of cars sold each month and reports it to the management at the end of the month. The management keeps the data in a file and assigns a number, 1 to 10, to each salesperson. The following statement declares an array, cars, of 10 components of type int to store the number of cars sold by each salesperson: int cars[10]; Write the code to store the number of cars sold by each salesperson in the array cars, output the total numbers of cars sold at the end of each month, and output the salesperson number selling the maximum number of cars. (Assume that data is in the file cars.dat, and that this file has been opened using the ifstream variable inFile.)

Short answer

Use an array to track sales, read data from a file, sum values for total sales, find max to identify top seller, and output results.

Step-by-step solution

Initialize Variables

Create the variables necessary to store data, such as an array for the sales data, variables for tracking the total number of cars sold, and to find the maximum value and the index of the maximum.

Read Data from File

Use a loop to read the number of cars sold by each salesperson from the 'cars.dat' file into the array. Ensure you use 'inFile' as it is the file stream variable initialized separately.

Calculate Total Cars Sold

Initialize a total counter to 0. Inside the loop, add the number of cars sold by each salesperson to this total to calculate the total number of cars sold.

Find Maximum Cars Sold

Using an additional loop, iterate over the array to determine the maximum number of cars sold and the corresponding salesperson number.

Output Results

Output the total number of cars sold and the salesperson number who sold the maximum. Ensure proper formatting for clarity of results.

Key concepts

File I/O

File input and output (File I/O) in C++ is an essential skill, especially when handling large amounts of data. In this exercise, the data for cars sold is stored in a file named `cars.dat`. To access this data, we use `ifstream`, a file stream class that allows us to read from files.
To begin, you'll use the `ifstream` object `inFile` to open the file. Make sure to include the fstream library with `#include ` at the top of your code. Once the file is opened successfully, you can read values from it sequentially using a loop. This is particularly useful for reading arrays since files often contain repeated, structured data like monthly sales figures.
Don't forget to check if the file was opened successfully by using `inFile.is_open()`. If the file fails to open, handle this in your program to prevent errors, perhaps by notifying the users or halting the program.

Loop Structures

Loop structures in programming allow you to perform repetitive tasks efficiently. In our exercise, loops are integral to reading data and processing the array of car sales.
Using a `for` loop, we can iterate over each salesperson's data, storing the number of cars each has sold in the `cars` array. The loop counter can easily represent which salesperson's data you are currently handling, thanks to the array's index.
Additionally, the same loop can calculate the total number of cars sold by summing up each array element. This efficiency is achieved because arrays allow you to access elements by index, and loops simplify repetitive tasks. Consider edge cases, like files with fewer entries, by limiting your loop to the data available.

Data Processing

Data processing is essential in converting raw data into meaningful insights. For the car sales data, processing involves several steps that help summarize and extract important information.
Firstly, accumulate the data from the file into an array. This structured storage enables easy access and manipulation. Next, calculate the total number of cars sold. This is done by summing all the elements of the array, leveraging the loop structure you've set up.
Subsequently, finding the maximum number of cars sold becomes a simple matter of comparing each element of the array to a maximum-tracking variable. The salesperson associated with this maximum value is then identified by keeping track of the corresponding index.

Algorithm Design

Algorithm design involves creating a step-by-step method for solving specific problems, like analyzing car sales in our example. Here, the algorithm is designed to read sales data, sum it up, and identify the highest number of cars sold.
The first step is to initialize necessary variables, including an array for sales data and variables to keep track of totals and maximums. Next, you read data from the file using a loop. This step is critical to ensure that all sales data is captured correctly.
The subsequent steps calculate the total and determine the maximum sales, using intuitive looping and condition-checking algorithms. Finally, the design includes outputting the results, formatted adequately to ensure clarity.
Through this process, algorithm design helps break down tasks into manageable operations, ensuring each part of the problem is addressed effectively.