1. ㅎㅎ Fourth step for Learning C++ Programming Call by value
Call by reference
Array
2-D Array
Array Searching
Bubble-Sort
Binary-Search

2. Call-by-value vs Call-by-reference
So far we looked at functions that get a copy of what the caller passed in.
- This is call-by-value, as the value is what gets passed in (the value of a variable).
We can also define functions that are passed a reference to a variable.
- This is call-by-reference, the function can change a callers variables directly.

3. Call-by-value vs Call-by-reference
A reference variable is an alternative name
for a variable. A shortcut.
A reference variable must be initialized to
reference another variable.
Once the reference is initialized you can treat it just like any other variable.

4. [ Practice 1 - defining and using a reference ]
[ex 1]

5. [ Practice 1 - defining and using a reference ]
[ex 1]
& is not the address operator
as part of the type identifier
& is the address operator
&rodents representing the address of the variable to which rodents refers

6. [ Practice 2 - defining and using a reference ]
[ex 2]

7. [ Practice 3 – Swap ]
[ex 3]

8. An array is a sequence of consecutive memory elements.
C++ Arrays
An array is a sequence of consecutive memory elements.
The contents of all elements are of the same type.
Could be an array of int, double, char, …
We can refer to individual elements by giving the position number (index) of the element in the array.
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9. int foo[6]; Each int is 4 bytes foo[0] foo[1] foo[5] 4 bytes
Memory and Arrays
4 bytes
Each int is 4 bytes
foo[0]
foo[1]
int foo[6];
foo[5]
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10. foo[17], foo[i+3], foo[a+b+c]
C++ Arrays
The first element is the 0th element!
If you declare an array of n elements, the last one is number n-1.
If you try to access element number n it is an error!
The element numbers are called subscripts:
foo[i]
A subscript can be any integer expression:
These are all valid subscripts:
foo[17], foo[i+3], foo[a+b+c]
10/2014

11. Initialization Rules for Arrays
1. int cards[4] = {3, 6, 8, 10};
//valid
2. int hand[4] = {};
3. hand[4];
//invalid
4. float hotelTips[5] = {5.0, 2.5};
//valid - hotelTips[0] = 5.0,
- hotelTips[1] = 2.5
5. long totals[500] = {0};
6. short things[] = {1, 5, 3, 8}; Ο Ο X O Ο Ο

12. [ Practice 4 - Array ]

13. [ Practice 4 - Array ]
index→
index →

14. [ Practice 5 - Array 2 ]

15. [ Practice 5 - Array 2 ]

16. 2-D Array: int A[3][4] Col 0 Col 1 Col 2 Col 3 Row 0 A[0][0] A[0][1]
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17. 2-D Array: char A[4][3] Memory Organization{
A[0][0]
A[0][1]
A[0][2]
A[1][0]
A[1][1]
A[1][2]
A[2][0]
A[2][1]
A[2][2]
A[3][0]
A[3][1]
A[3][2]
A[0]
A[1]
A[2]
A[3]
char A[4][3]; {
A is an array of size 4.
Each element of A is
an array of 3 chars { {
10/2014

18. [ Practice D Array ]

19. [ Practice D Array ]

20. [ Practice 7 - Array Searching ]

21. Bubble-Sort
10/2014

22. [ Practice 8 - Bubble Sort ]

23. Binary Search

24. Exercise

25. Result