1
00:00:05,700 --> 00:00:07,900
Welcome to the section 7 challenge.

2
00:00:08,300 --> 00:00:12,000
The purpose of this challenge is not to solve a specific problem

3
00:00:12,000 --> 00:00:14,600
but to give you a chance to practice with vectors.

4
00:00:15,100 --> 00:00:16,700
We'll declare two vectors,

5
00:00:16,700 --> 00:00:20,800
and we'll add these vectors to a two-dimensional vector that we'll declare as well.

6
00:00:21,300 --> 00:00:23,800
You'll get a chance to work with the vectors at,

7
00:00:23,800 --> 00:00:25,800
pushback and size methods.

8
00:00:26,300 --> 00:00:28,600
And you'll also work with a two-dimensional vector.

9
00:00:29,200 --> 00:00:32,800
Then at the end of this challenge, I'll ask you to modify a vector element

10
00:00:32,800 --> 00:00:36,600
and analyze the effect it has. You might be surprised by the result.

11
00:00:37,700 --> 00:00:42,000
Please go through the challenge in order and implement each of the directives in the challenge.

12
00:00:42,000 --> 00:00:44,300
Let's go over the details of this challenge together.

13
00:00:45,900 --> 00:00:50,500
First, I'd like you to declare two empty vectors of integers named vector1

14
00:00:50,500 --> 00:00:52,500
and vector2, respectively.

15
00:00:52,500 --> 00:00:56,800
Then add 10 and 20 to vector1 dynamically, using the pushback method.

16
00:00:57,460 --> 00:00:59,460
Display those two vector elements,

17
00:00:59,460 --> 00:01:02,960
using the at method as well as the size using the size method.

18
00:01:03,620 --> 00:01:06,620
Do the same thing for vector2, except we're going to add

19
00:01:06,620 --> 00:01:08,620
100 and 200 this time.

20
00:01:10,120 --> 00:01:14,480
Then I want you to declare an empty two-dimensional vector called vector2d.

21
00:01:14,880 --> 00:01:18,540
Remember, a two-dimensional vector is a vector of vectors.

22
00:01:19,040 --> 00:01:23,040
Then I want you to add vector1 to vector2d using pushback,

23
00:01:23,540 --> 00:01:27,140
then add vector2 to vector2d using pushback as well.

24
00:01:27,740 --> 00:01:30,740
Then display the elements in vector2d using the at method.

25
00:01:31,640 --> 00:01:34,540
Now comes the interesting part. I want you to change

26
00:01:34,540 --> 00:01:38,640
vector1's first element, using the at0 method.

27
00:01:38,790 --> 00:01:40,490
And I want you to change it to a 1000.

28
00:01:40,490 --> 00:01:43,190
Then i want you to display the elements in the 2d vector

29
00:01:43,190 --> 00:01:45,790
again using the at method, just like you did before.

30
00:01:46,150 --> 00:01:49,150
And then finally, display the elements in vector1.

31
00:01:49,750 --> 00:01:52,550
Take a look at the results and see if it's what you expected,

32
00:01:52,550 --> 00:01:54,050
and see what you think happened.

33
00:01:54,850 --> 00:01:59,450
That's it. Good luck, have fun. Once you finish the challenge, extend it any way you wish.

34
00:01:59,450 --> 00:02:02,450
Remember, the more you practice, the easier programming becomes.

35
00:02:02,750 --> 00:02:06,850
Once you finish the challenge, join me in the next video, and we'll go over my solution.