COMP 166 - Lab 5 - File I/O

Learning Outcomes and Introduction

In this lab assignment you will learn about:

• Opening and closing files with fopen and fclose
• Reading lines with fgets
• Interpretting file data with fscanf and sscanf
• Printing to files and stderr using fprintf

You will also practice using functions and loops, and translating mathematical expressions into code.

Task 1: Echoing Files

Create a program that prints the contents of input files to standard output.

Your program should accept a list of input file names to read as command-line arguments. If a file name is preceded by a "-a" switch, the contents of the file should be interpretted as a list of additional file names to open. Otherwise, each named file should be read and printed in the order given.

If any input file cannot be opened, or an error occurs during reading, print an error message to the standard error output and continue to the next input file.

Task 2: Formatted Input

Create a program that calculates statistics from a log of sensor data and prints a report to a file.

Your program should accept two command-line arguments: the name of the log file to read, followed by the name of the report file to write. If only one command-line argument is given, write the report to standard output instead. If no arguments are given, read the sensor data from standard input instead.

The log data your program processes will be formatted as a table of values. Each line of input will begin with a timestamp, followed by a list of floating-point sensor reading values (separated by white-space). The number of sensor readings on a line can vary from file to file, but every line in a file should have the same number of readings. Every line of input is guaranteed to be less than 500 characters long.

If the log data file cannot be opened, or an error occurs during reading, print an error message to the standard error stream and terminate the program. Similarly print an error message and exit if the log file contains any improperly formatted data or has an inconsistent number of sensor readings on each line.

The report generated by your program should display the timestamp that the minimum and maximum sensor values were recorded (across all readings). In addition, it should report the statistical mean (average) and standard deviation of the values in each column of sensor data.

Submission

Completing all tasks in this lab should result in 2 or more separate files within a single folder named like LastnameFirstname_lab5. Compress the folder into a ZIP archive and upload it to the D2L assignment.

The marks for this lab are heavily weighted towards good coding practice and style. Pay attention to your code formatting, use comments to clarify your code, and make sure you are using defines, arrays, loops, and functions effectively.

NOTE: This assignment is to be done individually. You can help one another with problems and questions, but in the end everyone must write and submit their own code.