A file is often used to store data for a program

1
Files (i)

• A file is often used to store data for a program

2
Files (ii)

• A file has an external name and is managed by the
  operating system

3
File Streams (i)

• A file stream is a one-way transmission path used
  to connect a data file to a C program
• An input file stream receives or reads data from
  a file into a C program
• An output file stream sends or writes data to a
  file from a C program

4
File Streams (ii)

• A distinct file stream object must be created for
  each file a C program uses

names.txt
include ltfstreamgt
C PROGRAM
grades.txt
ifstream
ofstream
ifstream
courses.csv
5
File Stream Functions (i)

• Begin by opening a file for reading or writing
• Use the open() function

6
File Stream Functions (ii)

• Functions to use in if stmts and while loops

7
File Stream Functions (iii)

• When youre done, be sure to close each file
• Use the close() function

8
In-Class Exercises

• Write a program to read in letters.txt
• Store each letter as an element in an array
• Ask the user to type in a number 1-26 and output
• The 23rd letter of the alphabet is W
• The 7th letter of the alphabet is G
• Write a program to read in numbers.txt
• Store each number as an element in an array
• Calculate the average, minimum, and maximum