1
00:00:00,180 --> 00:00:01,020
‫Welcome, Meg.

2
00:00:01,020 --> 00:00:07,020
‫In this video, I would like to show you my sample solution for the challenge for switch statements.

3
00:00:07,020 --> 00:00:09,210
‫And yeah, let's get started.

4
00:00:09,240 --> 00:00:14,520
‫So first of all, what we all need is a boolean and I'm going to call this one valid.

5
00:00:14,520 --> 00:00:21,750
‫So this will just take care of knowing whether we are talking about a valid or an invalid data type

6
00:00:21,750 --> 00:00:27,120
‫and valid or invalid depends on what the user entered after he entered a string.

7
00:00:27,120 --> 00:00:33,450
‫So first of all, he can enter a string and we will need a variable which will know of the value type

8
00:00:33,450 --> 00:00:37,830
‫because there are multiple different value types that I want to work with or data types.

9
00:00:37,830 --> 00:00:41,520
‫And then we are asking the user to enter something.

10
00:00:41,520 --> 00:00:47,670
‫So I'm just going to say enter a value and we're going to store this in this variable called input value.

11
00:00:48,060 --> 00:00:48,420
‫All right.

12
00:00:48,420 --> 00:00:55,380
‫The next thing that I want to ask the user is of which type he thinks the data is.

13
00:00:55,380 --> 00:00:58,950
‫So select the data type to validate the input you have entered.

14
00:00:58,950 --> 00:01:03,690
‫So plus one for string, two for Integer and three for Boolean.

15
00:01:04,500 --> 00:01:08,790
‫And now we of course need to check which of those is correct.

16
00:01:10,100 --> 00:01:17,750
‫Therefore, we first of all need to get the user input and we need to get the value that the user entered.

17
00:01:17,780 --> 00:01:23,270
‫So for example, if the user entered one input type, this variable here will be one.

18
00:01:23,300 --> 00:01:25,570
‫If we enter two, it will be two and so forth.

19
00:01:25,580 --> 00:01:29,750
‫So we convert whatever the user entered into an integer.

20
00:01:29,780 --> 00:01:33,830
‫Of course this could go wrong, so maybe you want to use tripods here instead.

21
00:01:33,830 --> 00:01:41,420
‫But I'm just going to assume that we are only entering one, two or three or in general numbers so our

22
00:01:41,420 --> 00:01:42,590
‫program doesn't crash.

23
00:01:42,620 --> 00:01:47,030
‫If you want to make sure that the program really doesn't crash, you could add a try and catch a block

24
00:01:47,030 --> 00:01:49,160
‫around here and that will definitely help.

25
00:01:49,160 --> 00:01:50,810
‫Or you could use try pass.

26
00:01:50,840 --> 00:01:51,140
‫All right.

27
00:01:51,140 --> 00:01:52,290
‫So that's free to you.

28
00:01:52,310 --> 00:01:54,410
‫I just kept it simple in this case.

29
00:01:54,410 --> 00:01:57,080
‫And we are focusing on switch case statements here.

30
00:01:57,080 --> 00:01:57,560
‫Right.

31
00:01:57,560 --> 00:02:00,740
‫So let's go ahead and create a switch case.

32
00:02:00,740 --> 00:02:04,160
‫So what is the switch case going to be interested in?

33
00:02:04,400 --> 00:02:10,490
‫Well, first of all, what we need is we want to know what the user has input.

34
00:02:10,490 --> 00:02:13,280
‫So was it one, two or three?

35
00:02:14,100 --> 00:02:19,520
‫Let's run the code for the case that it is a string.

36
00:02:19,530 --> 00:02:21,840
‫So for the case the user entered one.

37
00:02:22,230 --> 00:02:28,440
‫So we're going to create an extra method for this which checks whether everything that the user entered

38
00:02:28,440 --> 00:02:29,460
‫is alphabetic.

39
00:02:29,460 --> 00:02:30,990
‫So if it's a string.

40
00:02:32,600 --> 00:02:36,650
‫Let's look at this method is alphabetic before we go any further.

41
00:02:37,040 --> 00:02:39,500
‫So we're going to create this a little.

42
00:02:40,510 --> 00:02:44,800
‫Method outside of our static void main method.

43
00:02:44,800 --> 00:02:46,680
‫So I'm going to put it over here.

44
00:02:46,690 --> 00:02:53,170
‫We need to make sure that it is static because we're not creating an object of this class, so we cannot

45
00:02:53,170 --> 00:02:54,130
‫otherwise use it.

46
00:02:54,130 --> 00:02:56,050
‫So it needs to be static in this case.

47
00:02:56,050 --> 00:02:59,170
‫Then we are returning a boolean.

48
00:02:59,170 --> 00:03:03,640
‫So this method is going to return a bool and we say is all alphabetic.

49
00:03:03,640 --> 00:03:04,960
‫That's the name of the method.

50
00:03:05,050 --> 00:03:07,660
‫We need a string, the value that is passed.

51
00:03:07,660 --> 00:03:14,560
‫And then what we do is for each character in value, for each C, which is a character in our value,

52
00:03:14,560 --> 00:03:15,280
‫which is a string.

53
00:03:15,280 --> 00:03:16,240
‫So we can do that.

54
00:03:16,240 --> 00:03:20,230
‫What we want to check is if the char is a letter.

55
00:03:21,190 --> 00:03:24,040
‫And if it is not a letter, then we return.

56
00:03:24,040 --> 00:03:24,400
‫False.

57
00:03:24,400 --> 00:03:30,640
‫So this whole boolean will be false if it went through the whole string here for this whole value and

58
00:03:30,640 --> 00:03:36,850
‫each of them is a character that is of type letter, then it will return.

59
00:03:36,850 --> 00:03:37,400
‫True.

60
00:03:37,420 --> 00:03:43,600
‫So basically let's say we have a text here which is Hello World.

61
00:03:43,930 --> 00:03:49,930
‫Then it will go through every single one of those letters here or characters it will check.

62
00:03:49,960 --> 00:03:51,460
‫Is this a letter.

63
00:03:52,340 --> 00:03:52,900
‫Then.

64
00:03:52,910 --> 00:03:55,070
‫Is this a letter?

65
00:03:55,070 --> 00:03:55,850
‫And so forth.

66
00:03:55,850 --> 00:03:57,890
‫And each time it's going to see.

67
00:03:58,760 --> 00:04:00,830
‫This is, in fact, a letter.

68
00:04:01,340 --> 00:04:06,680
‫And that's why it's going to go through this for each loop without returning false at any point.

69
00:04:06,680 --> 00:04:08,270
‫And it will return true.

70
00:04:08,900 --> 00:04:18,200
‫And then let's say we had hello world with a zero here instead and this would be a three because we

71
00:04:18,200 --> 00:04:23,690
‫are cool and all of that and then that would be returning false.

72
00:04:23,690 --> 00:04:24,530
‫So it would check.

73
00:04:24,560 --> 00:04:25,820
‫Is this a letter.

74
00:04:25,820 --> 00:04:26,960
‫Yes, that's true.

75
00:04:27,080 --> 00:04:28,430
‫Is this here letter?

76
00:04:28,700 --> 00:04:29,660
‫No, it's not.

77
00:04:29,660 --> 00:04:31,430
‫So this whole statement is false.

78
00:04:31,430 --> 00:04:34,880
‫So it returns out of this whole method and will return.

79
00:04:36,080 --> 00:04:36,680
‫False.

80
00:04:38,370 --> 00:04:38,670
‫Okay.

81
00:04:38,670 --> 00:04:40,560
‫So now we can get back to our case.

82
00:04:40,560 --> 00:04:43,710
‫One we say valid is alphabetic.

83
00:04:43,710 --> 00:04:46,500
‫So we pass in the input value, which is our.

84
00:04:47,290 --> 00:04:49,300
‫String here that the user has entered.

85
00:04:49,300 --> 00:04:51,910
‫So whatever the user has entered, we check is it alphabetic?

86
00:04:51,910 --> 00:04:56,410
‫And we say input value type is string.

87
00:04:58,290 --> 00:04:59,940
‫And then we break out of it.

88
00:05:00,000 --> 00:05:05,970
‫By the way, this ballot will now be the result, of course, of whatever is all alphabetic return based

89
00:05:05,970 --> 00:05:07,320
‫on the input that we gave it.

90
00:05:07,740 --> 00:05:13,230
‫And now let's look at the second case where the user entered an integer.

91
00:05:14,130 --> 00:05:18,360
‫So here we set the user enter two and it was an integer.

92
00:05:18,360 --> 00:05:21,840
‫So we check is the return value zero.

93
00:05:22,110 --> 00:05:26,640
‫And then we check in, try parse input value.

94
00:05:26,670 --> 00:05:33,660
‫So we pass in our string, we try to parse it, and if it works, then valid will be true.

95
00:05:33,660 --> 00:05:35,730
‫And if it didn't work, then it will be false.

96
00:05:35,730 --> 00:05:41,150
‫And whatever was output when it was correct will be in red value.

97
00:05:41,160 --> 00:05:44,170
‫And then we say the input value type was an integer.

98
00:05:44,190 --> 00:05:45,540
‫We break out of it.

99
00:05:45,900 --> 00:05:49,470
‫Now the next case is our case three.

100
00:05:49,980 --> 00:05:53,400
‫And here we are checking boolean red flag.

101
00:05:53,400 --> 00:05:55,230
‫And of course you could also use bool here.

102
00:05:55,230 --> 00:05:56,610
‫You don't need to use boolean.

103
00:05:58,360 --> 00:05:59,560
‫Red flag.

104
00:06:00,010 --> 00:06:03,130
‫It's going to be false in this case, the returned flag.

105
00:06:03,130 --> 00:06:08,380
‫And we use tripods here again, you can see we can use Troy Powers for integers, but we can also use

106
00:06:08,380 --> 00:06:09,370
‫it for booleans.

107
00:06:09,970 --> 00:06:13,900
‫And here bool dot try parse with the input value.

108
00:06:14,080 --> 00:06:19,450
‫If the input value in fact was a boolean, then destroy parse will return true.

109
00:06:19,450 --> 00:06:22,870
‫Otherwise it will return false and that will be stored invalid.

110
00:06:22,990 --> 00:06:27,010
‫And whatever the result of this trespass will be, will be stored in red flag.

111
00:06:27,010 --> 00:06:33,250
‫So if it was a boolean then red flag will be true and our valid will also be true and we set our input

112
00:06:33,250 --> 00:06:34,540
‫value type two boolean.

113
00:06:34,900 --> 00:06:37,690
‫And now finally we need to have a default case.

114
00:06:37,690 --> 00:06:41,590
‫So let's say the user entered anything but one, two and three.

115
00:06:41,920 --> 00:06:46,030
‫Then we will just say not able to detect the input type.

116
00:06:46,030 --> 00:06:48,760
‫Something is wrong and we break out of it.

117
00:06:50,130 --> 00:06:55,350
‫And now we just tell the user if it was validly input.

118
00:06:55,350 --> 00:07:03,180
‫So if he considered whatever he input correctly and we just say and by the way, this should be one

119
00:07:03,300 --> 00:07:04,440
‫line further in.

120
00:07:04,500 --> 00:07:12,450
‫So we just say you have entered a value input value and then we check is the value valid?

121
00:07:12,720 --> 00:07:16,410
‫And then we say if it was valid console red line, it is valid.

122
00:07:16,410 --> 00:07:20,970
‫And then we say of which input value type it was.

123
00:07:21,000 --> 00:07:24,510
‫Now you see it says use of unassigned local variable input value type.

124
00:07:24,510 --> 00:07:30,990
‫So we are assigning a value here, but we're only assigning it in switch and not in all of its outputs.

125
00:07:30,990 --> 00:07:34,740
‫So for example, in the default, we don't have an output for our input value type.

126
00:07:34,740 --> 00:07:37,050
‫So there are two ways of what we could do.

127
00:07:37,080 --> 00:07:44,220
‫We could say input value type is equal unknown and then the error would disappear.

128
00:07:44,490 --> 00:07:51,300
‫Alternatively, what we could have done is we could have said that our input value type is string dot

129
00:07:51,300 --> 00:07:52,020
‫empty.

130
00:07:53,260 --> 00:07:54,580
‫That would have been an alternative.

131
00:07:54,580 --> 00:08:00,610
‫And you can see the error also disappears, even though I like this variant more because it's just unknown

132
00:08:00,610 --> 00:08:02,580
‫and we're going to tell that to the user.

133
00:08:02,590 --> 00:08:08,290
‫So these are the two options that you had here, but I'm just going to keep it like such.

134
00:08:09,850 --> 00:08:12,160
‫All right, now let's run it.

135
00:08:14,090 --> 00:08:19,790
‫And as a value, I'm going to enter 13 and now let's say it is an integer.

136
00:08:20,330 --> 00:08:22,160
‫You have entered a value 13.

137
00:08:22,160 --> 00:08:23,570
‫It is a valid integer.

138
00:08:23,600 --> 00:08:25,250
‫All right, now let's try it again.

139
00:08:25,610 --> 00:08:32,420
‫This time I'm going to enter Hello World and I'm going to think it's an integer and you have entered

140
00:08:32,420 --> 00:08:35,360
‫a value Hello world it is an invalid integer.

141
00:08:35,720 --> 00:08:41,930
‫Okay, now let's check it once again with true and I think it's a boolean and you have entered a value.

142
00:08:41,940 --> 00:08:42,470
‫True.

143
00:08:42,470 --> 00:08:44,330
‫It is a valid boolean.

144
00:08:45,190 --> 00:08:45,820
‫All right.

145
00:08:46,440 --> 00:08:54,630
‫So now you have this little program which allows you to enter a value and then try to say what kind

146
00:08:54,630 --> 00:08:55,980
‫of data type it is.

147
00:08:57,700 --> 00:09:04,690
‫So we have used switch statements, tripods, and we even used if statements as well as.

148
00:09:05,560 --> 00:09:07,180
‫Hey, for each loop here.