Exam Final Review
Tom Kelliher, CS 116 Dec. 9, 2002
1
Administrivia
Announcements Lab and postlab 7 due today. Extra credit applet due Wednesday. Final Friday in HS 153 3:00 to 5:00.
2
Example
This example pulls together a lot of what we've done this semester. 1. A stack is a fundamental data structure in CS. 2. Last in, first out (LIFO) principle: like a stack of trays in a cafeteria line. 3. Stack parameter: number of items stack can hold. 4. Stack state: data within the stack (array), top of stack. 5. Stack operations: empty, full, push, pop. Integer stack implementation: 1
import java.applet.*; public class Driver extends Applet { Stack s; public void init() { int tempI; boolean tempB; s = new Stack(10); tempB = s.empty(); s.push(12); tempB = s.empty(); s.push(9); tempI = s.pop(); tempI = s.pop(); tempB = s.empty(); } } class Stack { int topIndex; int data[]; public Stack(int length) { topIndex = -1; data = new int[length]; } boolean empty() { if (topIndex == -1) return true; else return false; } boolean full() { if (topIndex == data.length - 1) return true; 2
// Returns true. // Returns false. // Returns 9. // Returns 12. // Returns true.
else return false; } int pop() { if (empty()) { // Throw an exception and return. return 0; } else { topIndex--; return data[topIndex + 1]; } } void push(int newTop) { if (full()) { // Throw an exception and return. } else { topIndex++; data[topIndex] = newTop; } } }
3
Control and Calculation
1. Iterative execution: while, for, and do/while loops. When to use? Index variable. 2. Conditional execution: if/else if/else, switch, break. Purpose of the break within a switch case. 3
3. Conditions -- keys to the above. Precedence, associativity, operators. Remember the precedence table. 4. Arithmetic: Operators and their types. Type conversion: implicit and explicit casts.
4
Methods
1. Parameter passing: Formal and actual parameters. 2. Pass by reference vs. pass by value. 3. Local variables. 4. Return values and the type of a method. 5. Special applet methods: init, paint, interface methods for listeners. 6. Special class methods: The constructor.
5
Data
1. Primitive types: int, double, boolean, char, etc. 2. Arrays: Type, number of elements, declaring, indexing, .length. 3. Objects: String, Label, TextField, etc. Creating your own. 4. Declaring and instantiating. The actual variable or a refe...