Table of Contents
I. Software Systems and Methodology – 40%
A. Data organization
1. Data types
a. Definition: Data types are assigned to blocks of information. The type tells the program how to handle the specific information. For example, an integer data type can be multiplied, but a Boolean data type cannot.
b. In C, we have a data type called a struct that allows us to create records with fields. Declare a struct variable using the form
struct node { int age;
char gender;}
To access a field in the record use the form “node->age;”.
c. A pointer is an unusual type. The value that it holds is a memory address. We then use the memory address to manipulate the data held at that memory address. In Pascal, to declare a pointer use:
type Link = type-name;
If you want to manipulate the memory address, then use the before the variable name. For example, H means, “points to H”. If you want to manipulate the data, then use the after the variable name. So, H means “H points at this data”. Remember that we read English left to right; this might help you remember what the operator does in which position. In C, to declare a pointer, use the * operator: int *p;. To store the address of a variable v in the pointer p use the statement p = &v; The ampersand (&) is the operator that returns the address instead of the value. Finally, to store a value in the pointer use the * operator again; for example, *p = v; will store the value of v at the location of p.
