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Today’s topics
•Stack, Queue implementations
•Start Editor Buffer case study
Reading
•Ch 10 & 9
Lec ture #20
Text editor case study
Command-line text editing commands
!F! Move cursor forward one character position!
!B! Move cursor backward one character position
!J! Jump to start of buffer (before first character)
!E! Move cursor to end of buffer (after last character)!
!Ixxx Insert characters xxx at current cursor position
!D! Delete character after current cursor position
Buffer requirements
•Sequence of characters + cursor position
•Operations to match commands above
What to learn?
•Implementation choices, performance implications
Buffer class interface
class Buffer {
public:
Buffer();
~Buffer();
void moveCursorForward();
void moveCursorBackward();
void moveCursorToStart();
void moveCursorToEnd();
void insertCharacter(char ch);
void deleteCharacter();
void display();
private:
// TBD!
};
Buffer layered on Vector
Need character data + cursor
•Chars in Vector<char>
•Represent cursor as integer index
•Minor detail -- is index before/after cursor?
Buffer contains: AB|CDE
// for Buffer class
private:
Vector<char> chars;
int cursor;
A B EDC
2
cursor
