Objective:
The objective of this lab is to get you some experience in processing strings character by character and in implementing stacks and queues in a class package.
The programming assignment:
In your lab05, replace instructor’s Tokenizer class and MyStackQueue package with your own. Requirements:
1. You must use a linked list to implement your queue.
2. You must use an array to implement your stack.
3. You must use the following frame work to implement your tokenizer.
class Tokenizer {
private char [] Buf;
private int cur;
Tokenizer(String infixExpression) {
Buf = infixExpression.toCharArray(); cur = 0;
}
boolean moreTokens() { Skip blanks.
return cur<Buf.length; }
Token nextToken() {
- Skip blanks.
- if (cur>=Buf.length) return null;
- If the next character is a digit, keep reading until a non-digit is read. Convert the string of digits into an integer.
String Digits = new String(Buf, start, len); int num = Integer.valueOf(Digits).intValue();
} }
Use num to create and return an operand.
4. Otherwise, use the next character to create and return an operator.
