1
00:00:02,650 --> 00:00:10,220
Using no pointer, so a pointer could point to anywhere in the memory installed on your computer.

2
00:00:10,240 --> 00:00:15,940
So and then assignment that the reference pointer means that you could potentially write over since

3
00:00:15,940 --> 00:00:24,220
the memory used by operating systems so or write memory used by hardware on your machine.

4
00:00:24,220 --> 00:00:31,030
However, the operating systems will usually give an executable a specific memory range that it can

5
00:00:31,030 --> 00:00:34,000
access, and it tends to access memory.

6
00:00:34,000 --> 00:00:42,730
And if it attempts to access memory out of this range, it will cause an operating system memory access

7
00:00:42,730 --> 00:00:43,890
violation.

8
00:00:43,900 --> 00:00:53,560
So for this reason, you should almost always obtain pointer values using the end operator here or from

9
00:00:53,560 --> 00:00:55,990
a call to an operating system function.

10
00:00:55,990 --> 00:00:59,880
So you should not give a pointer, an absolute address.

11
00:00:59,890 --> 00:01:06,190
The only exception to this is the C++ constant for invalid memory address.

12
00:01:06,190 --> 00:01:07,540
No TR here.

13
00:01:07,540 --> 00:01:09,730
So for example, let's define the point here.

14
00:01:10,570 --> 00:01:15,700
Let's define the P pointer here and assign it as new beta.

15
00:01:15,880 --> 00:01:21,100
Here you add the code and integer A 62.

16
00:01:21,960 --> 00:01:24,510
And then assign p.

17
00:01:25,920 --> 00:01:31,260
R a variable, a integer variable here and called here as well.

18
00:01:32,090 --> 00:01:34,040
For example, just an example code.

19
00:01:34,220 --> 00:01:36,290
We won't write it in this lecture here.

20
00:01:36,620 --> 00:01:44,240
So if our new Peter not equals to P, then.

21
00:01:45,420 --> 00:01:48,180
See out STD.

22
00:01:49,620 --> 00:01:50,270
Here.

23
00:01:50,310 --> 00:01:52,560
See out here.

24
00:01:53,310 --> 00:01:54,090
And.

25
00:01:55,210 --> 00:02:00,850
P list asterisk here and and here.

26
00:02:01,870 --> 00:02:03,370
So this code.

27
00:02:03,400 --> 00:02:09,840
Initialize the pointer pointer P to null Peter.

28
00:02:10,600 --> 00:02:12,590
We get an error here and line.

29
00:02:12,610 --> 00:02:13,180
Yes.

30
00:02:13,720 --> 00:02:18,310
So this code initialized p to new Peter later in the code.

31
00:02:18,760 --> 00:02:23,530
The pointer is initialized to the address of an integer variable.

32
00:02:24,160 --> 00:02:30,510
So still later in the code, the pointer is used by the rather than calling it immediately.

33
00:02:30,520 --> 00:02:37,740
So the pointer is first check to ensure that it has been initialized to a non null value.

34
00:02:37,750 --> 00:02:44,520
So the compiler will check to see if we are able to use a variable that has not been initialized.

35
00:02:44,530 --> 00:02:51,340
But if you're writing library code, the compiler will not know whether the colors of your code will

36
00:02:51,340 --> 00:02:53,780
use pointers correctly.

37
00:02:53,800 --> 00:02:56,360
So the type here type of constant.

38
00:02:56,360 --> 00:02:59,120
No, Peter is not an integer.

39
00:02:59,140 --> 00:03:01,780
It is here sdd.

40
00:03:02,950 --> 00:03:11,080
No p t r t variable, so all pointers type can be implicitly converted to this type.

41
00:03:11,380 --> 00:03:18,160
So no p t r can be used to initialize variables of all pointer types.