WEBVTT 00:00.830 --> 00:08.310 In this lecture I want to go over some simple input so we can start making some more interesting programs. 00:08.780 --> 00:16.870 An input will come up again and again but for now we're going to keep this very simple so we can just 00:17.220 --> 00:21.330 we just have something easy for us to to work with for now. 00:21.950 --> 00:29.520 So we've already seen how to output something to the console. 00:29.740 --> 00:32.200 And we did this using C out. 00:32.770 --> 00:38.020 And what is called the extraction operator. 00:38.070 --> 00:48.880 So this is the three here these two arrows are the extraction operator and we can chain them together 00:48.910 --> 00:49.690 like this 00:52.770 --> 00:57.640 so your I-ness say hello everybody. 00:57.640 --> 00:58.340 Right. 00:58.810 --> 01:13.620 So this sea out has this extraction operator and the way I remember it is the text here. 01:13.630 --> 01:14.660 Hello everybody. 01:14.980 --> 01:25.360 And the Endal will sort of funnel into sea out so the arrows kind of show where the data is going in 01:25.360 --> 01:26.680 the sense. 01:26.680 --> 01:34.240 So if we have something called Sea Ouch you'd still stand to reason that we'd have something called 01:34.240 --> 01:36.310 Sea in. 01:36.440 --> 01:46.070 So if out is the output to the console in would be in from the console and if you think that you would 01:46.070 --> 01:47.430 be right here. 01:47.750 --> 01:49.860 In fact you're exactly right. 01:50.060 --> 01:58.670 There is something called Sea in and let's try an example of how to get some input from the console. 01:58.670 --> 02:07.690 So we have char char input and let's just say Please enter character 02:10.780 --> 02:12.090 this. 02:12.580 --> 02:13.200 The Endal 02:16.020 --> 02:25.160 will say seen and noticed how this operator which is called the extraction operator is the opposite 02:25.190 --> 02:33.190 of the sea out insertion operator see char input. 02:33.190 --> 02:48.700 CH So again how I remember it is c in will put things into and there's little arrows into this. 02:48.710 --> 02:57.750 In this case this char variable and the opposite for sea out say see Ouch. 02:58.410 --> 02:59.350 Character 03:01.500 --> 03:04.220 inputted is 03:07.730 --> 03:09.020 share in 03:12.010 --> 03:16.170 so let's see what happens if you're in this. 03:16.360 --> 03:22.550 So please insert character and notice how it's waiting. 03:22.700 --> 03:31.260 It doesn't just do this line 16 and line 17 and line 19. 03:31.390 --> 03:37.250 It's actually waiting on line 17 right now for you to actually input something. 03:37.300 --> 03:50.690 So as input he and you press enter and then it'll it'll actually stop blocking on inputs and go to the 03:50.690 --> 03:52.330 next line. 03:52.990 --> 03:55.470 So this is very important. 03:56.510 --> 04:02.090 This is a very important concept that will matter a lot later on. 04:02.600 --> 04:08.630 So I put in e and it outputted that I inputted. 04:08.810 --> 04:13.440 So let's run that again just to make sure we're not it's not crazy. 04:13.520 --> 04:19.440 Say a W and character you input is a W. 04:20.050 --> 04:26.990 So just to show that it doesn't just work on char's Let's put like an integer here. 04:27.060 --> 04:38.470 It's called input. 04:38.640 --> 04:39.290 Put ch 04:44.150 --> 04:59.510 in say Please enter a number number and the number you see number 10 and the number you inputted is 04:59.520 --> 05:00.190 10. 05:00.260 --> 05:01.040 So it works. 05:01.060 --> 05:05.220 So cnt both see an NCO work on different types. 05:05.280 --> 05:06.800 I can even have a float 05:09.130 --> 05:12.070 in to see if input 05:18.250 --> 05:30.700 this in again or favorite number one for and it's three point one for. 05:30.720 --> 05:38.600 So just like the distraction operator for C Ouch which could Schene multiple things together a line 05:38.610 --> 05:56.390 20 year we're chaining this tax rate here class the input plus the Endal and also chain multiple input 05:56.420 --> 06:13.540 see either say if input to these Enter say two numbers and I'm going to say with space tween and I'm 06:13.680 --> 06:16.390 going to change to the next one. 06:16.470 --> 06:29.570 So if input to output here so you know say the first number you inputted and then out. 06:29.640 --> 06:37.040 CH The second number put in. 06:37.460 --> 06:41.960 If that's the word that's used for now. 06:42.070 --> 06:47.620 Input to Andell. 06:47.750 --> 06:49.110 Let's run that. 06:56.350 --> 06:56.960 Going. 06:56.990 --> 06:58.410 Always have the semi-colon. 06:58.440 --> 07:02.730 Very important as compiler will complain to you. 07:03.130 --> 07:12.470 So let's say three point one for in 6 3 9. 07:12.470 --> 07:13.220 Sure. 07:13.330 --> 07:22.150 And I notice there's a space in between you enter so and that puts exactly what we thought. 07:22.160 --> 07:26.550 First one is Threepio and for the next one is six point eight. 07:26.740 --> 07:35.300 The reason why we need to have the space in between is c in this extraction operator actually ignores 07:35.810 --> 07:44.550 whitespace so a space would be a white space to be tambour the space bar or return line. 07:44.720 --> 07:46.480 Something like this. 07:46.520 --> 07:54.100 So let's run this again and say let's give it a bunch of space and then we'll enter three. 07:54.200 --> 08:00.530 Another bunch of space and 23 and maybe more space after. 08:00.550 --> 08:06.370 So still it just ignores the whole thing and then reads the float. 08:06.370 --> 08:07.470 In this case. 08:07.720 --> 08:15.350 And then again ignores all of the whitespace and then reads the next number 23 and outputs. 08:16.380 --> 08:27.750 So just remember that the extraction operator is what ignores all the whitespace not see it. 08:28.490 --> 08:38.440 So this is enough to get started for some simple programs that we're going to be working on in the next 08:38.440 --> 08:39.500 few lectures.