1. Speaker: Liu Yu-Jiun Date: 2009/4/15
Recitation Course 0415
Speaker: Liu Yu-Jiun
Date: 2009/4/15

2. Outline
review
exercise

3. Chapter 3 – Class and Objects

4. // rational.h
#include <iostream>
using namespace std;
class RationalNumber{
public:
RationalNumber(int = 0, int = 1);
RationalNumber operator+(const RationalNumber&);
RationalNumber operator-(const RationalNumber&);
RationalNumber operator*(const RationalNumber&);
RationalNumber operator%(const RationalNumber&);
private:
int numerator;
int denominator;
bool sign;
void reduction(void);
int gcd(int, int); };
Class內所有的成員與成員函式都預設為private。若要讓class外部的程式使用，就得設定為public。
如果沒有定義建構子，系統也會給一個預設的建構子和解構子。

5. Chapter 4 & 5 – control statement

6. Control Structure Three control structures Sequence structure
Programs executed sequentially by default
Selection structures
if, if...else, switch
Repetition structures
while, do...while, for

7. Fig. 4.2 | Sequence-structure activity diagram.
total = total + grade;
counter = counter + 1;
Fig. 4.2 | Sequence-structure activity diagram.

8. if

9. Fig. 4.4 | if single-selection statement activity diagram.
if (grade >= 60)
cout << “Passed”;
Fig. 4.4 | if single-selection statement activity diagram.

10. if...else

11. Fig. 4.5 | if...else double-selection statement activity diagram.
if (grade >= 60)
cout << “Passed”;
else
cout << “Failed”;
cout << (grade >= 60 ? “Passed” : “Failed”)
Fig | if...else double-selection statement activity diagram.

12. 4.6 if…else Double-Selection Statement (Cont.)
Ternary conditional operator (?:)
Three arguments (condition, value if true, value if false)
Code could be written:
cout << ( grade >= 60 ? “Passed” : “Failed” );
Condition
Value if true
Value if false

13. while loop

14. Fig. 4.6 | while repetition statement UML activity diagram.
int product = 3;
while (product <= 100){
product = 3 * product }
Fig. 4.6 | while repetition statement UML activity diagram.

15. for loop

16. Fig. 5.3 | for statement header components.

17. Fig. 5.4 | UML activity diagram for the for statement in Fig. 5.2.
for (int c = 1 ; c <= 10 ; c++){
cout << c << “ ”; }
Fig. 5.4 | UML activity diagram for the for statement in Fig. 5.2.

18. 5.3 for Repetition Statement
General form of the for statement
for ( initialization; loopContinuationCondition; increment ) statement;
Can usually be rewritten as:
initialization; while ( loopContinuationCondition )
{ statement; increment; }

19. do...while

20. Fig. 5. 8 | UML activity diagram for the do
Fig. 5.8 | UML activity diagram for the do...while repetition statement of Fig. 5.7.

21. switch

22. 5.6 switch Multiple-Selection Statement
switch statement
Used for multiple selections
Tests a variable or expression
Compared against constant integral expressions to decide on action to take
Any combination of character constants and integer constants that evaluates to a constant integer value

23. 5.6 switch Multiple-Selection Statement (Cont.)
switch statement (Cont.)
default case
Executes if no matching case label is found
Is optional
If no match and no default case
Control simply continues after the switch

24. Fig. 5.12 | switch multiple-selection statement UML activity diagram with break statements.

25. Chapter 6 – Function and Template

26. Components of Function (L4.2)
Function prototype
int compare(int, int);
Function call
int main(){
int a = 3, b=4;
int bigger;
bigger = compare(a, b); }
Function definition
int compare(int v1, int v2){
if (v1 < v2) return v2;
else return v1;

27. Function Call
Call by value
Call by reference
Call by pointer(address)

28. Call by Value 不影響原本的值 需要較多的記憶體空間 void swap(int a, int b){ ...... }
int main(){
int c = 3, d = 5;
swap(c, d); a 3
0x23ff50 5 b
0x23ff54
... c 3
0x23ff70 5
0x23ff74 d
不影響原本的值
需要較多的記憶體空間

29. Call by Reference 會影響原本的值 節省記憶體空間 void swap(int &a, int &b){ ...... }
int main(){
int c = 3, d = 5;
swap(c, d); a c 3
0x23ff50 5 b d
0x23ff54
會影響原本的值
節省記憶體空間

30. Call by Pointer(address)
void swap(int *a, int *b){
...... }
int main(){
int c = 3, d = 5;
swap(&c, &d); a
0x23ff70
0x23ff50
0x23ff74 b
0x23ff54
... c 3
0x23ff70 5
0x23ff74 d
會影響原本的值
需要較多的記憶體空間

31. Function Function overloading return_value_type Name (parameters);
Closely related tasks
Same name
Different sets of parameters (number or type)
利用傳入不一樣的參數做類似，但又不完全相同的工作。

32. Function Overloading Allow function overloading in C++
different parameter number
different parameter data types (different order)
Different const
Disallow function overloading
Different return parameter
Different reference
Default argument
Different const只是表示參數列使用的是const或非const也能區別

33. Different Return Parameter
void nothing(int a){}
int nothing(int a){ return a;}
void nothing(int a){}
int nothing(int a, int b){ return a+b;}

34. Different Reference Function signature: @nothing$qi @nothing$qri
void nothing(int a){}
void nothing(int &a){}
int main(){
int b = 3;
nothing(b);
return 0; }
@nothing$qi
@nothing$qri

35. Function Templates More compact and convenient form of overloading
Identical program logic and operations for each data type
Function template definition
Written by programmer once
Begins with the template keyword
Contains template parameter list of formal type parameters for the function template enclosed in angle brackets (<>)
Formal type parameters
Preceded by keyword typename or class
Placeholders for fundamental types or user-defined types

36. Function Templates template <class T, class S>
T test(T v1, T v2, S v3){
if (v1 > v2){
cout << v3 << endl;
return v1; }
else {
return v2;
int main(){
int a = 3, b = 5;
string s1 = "int compare";
cout << test(a, b, s1) << endl;
double c = 4.67, d = 4.15;
string s2 = "double compare";
cout << test(c, d, s2) << endl;