Reading on Text Files

Introduction

Many applications involve analysis of data found in a file (e.g., a spreadsheet or text-based documenbt). As an example, this reading outlines several approaches to the following problem.

Problem

File class-tests.dat shows test scores for a hypothertical class. The file is organized as follows:

• The first four lines contain title information and column headers.
• Data for each class member is on its own line.
• The name appears in columns 1-20
• Test 1 is located in columns 21-30.
• Test 2 is located in columns 31-40.
• Test 3 is located in columns 41-end.
• No line of data contains more than 50 characters.

A program is to be created to print scores for a designated test or the average test score for each person, according to a command-line parameter:

• print name and scores for test 1 if command line parameter is 1
• print name and scores for test 2 if command line parameter is 2
• print name and scores for test 3 if command line parameter is 3
• print name and average on the three tests if command line parameter is all

Approach 1: Read name into array and read scores with fprintf

class-tests-1.c

Approach 2: Read full line at a time

class-tests-2.c

http://www.walker.cs.grinnell.edu/courses/161.fa11/modules/module-comm-line-files/reading-files-2.shtml