1. Lecture 25 The Tao that can be talked about is not the true Tao
Opening line of Tao Te Ching

2. Arrays
Remember strings. They are collections of characters which are stored in memory sequentially. We want to be able to have a sequence of variables of any type. There are many applications when this would be helpful.

3. Arrays
Pascal offers arrays to address this problem. Array is simply a sequence of variables of some type addressable via index. For example:
TYPE IntegerArray = ARRAY[1..5] of integer;
Size or
range
Type
name
Basic
type of
element
Type
keyword
Array
keyword

4. Arrays TYPE IntegerArray = ARRAY[1..5] of integer;
You can now do this:
VAR aMyArray : IntgerArray;
That is, you can now have a variable of this type!
What does this new variable look like in memory?
aMyArray[ 1 ]
aMyArray[ 2 ]
aMyArray[ 3 ]
...

5. Arrays You can have arrays of any basic types
TYPE CharArray = ARRAY[1..10] of char;
TYPE BoolArray = ARRAY[1..100] of boolean;
TYPE RealArray = ARRAY[1..7] of real;
TYPE NegIntArray = ARRAY[ ] of boolean;
TYPE WhatIsThis = ARRAY[‘a’..’z’] of integer;

6. Numbers in reverse
Write a program which reads in integers into an array and then prints them in reverse.

7. Grades histogram

8. Letter frequency
Write a program which reads in several English sentences and displays letter frequency histogram

9. Home work
Read 10.1,10.2
Hw #7 due Monday, December 14th (ABSOLUTE DEADLINE)
Optional problems: page 473 #1, 2, 6, 13, 15
Look at last year’s final
Start reviewing

10. Programs from this lecture
Numbers in reverse
Grade histogram1
Grade histogram2
Letter frequency