Java/C2/Relational-Operations/English-timed

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Time Narration
00:01 Welcome to the spoken tutorial on Relational Operators in Java.
00:07 In this tutorial, we will learn about the
00:09 boolean data type,
00:10 Relational operators and
00:12 how to compare data using Relational operators.
00:17 For this tutorial, we are using:

Ubuntu 11.10, JDK 1.6 and Eclipse 3.7

00:26 To follow this tutorial, you must have knowledge of data types in Java.
00:31 If not, for relevant tutorials, please visit our website as shown.
00:39 Relational operators are used to check for conditions.
00:43 Their output is a variable of boolean data type.
00:48 A boolean data type is of size 1 bit.
00:51 It stores only two values.
00:54 true or false.
00:56 true is the output when the condition is true.
00:59 false is the output if the condition is not true.
01:06 Here is a list of the relational operators available.
01:10 * greater than
01:12 * less than
01:13 * equal to
00:14 * greater than or equal to
01:15 * less than or equal to
01:17 * not equal to
01:19 We shall look into each of them in detail.
01:22 Switch to Eclipse.
01:27 Here we have the Eclipse IDE and the skeleton required for the rest of the code.
01:33 I have created a class BooleanDemo and added the Main method.
01:38 Now let us add some expressions.
01:41 Type boolean b ;
01:47 The keyword boolean declares the data type of the variable b as boolean.
01:53 We shall store the result of our condition in b.
01:58 We shall define a variable weight and check for a condition using that variable.
02:05 int weight equal to 45;
02:13 We shall check if the value in weight is greater than 40.
02:18 b equal to weight greater than 40;
02:28 This statement says: check if the value of variable is greater than 40 and store the result in 'b'.
02:37 Now, let us print the value of 'b'.
02:41 System dot out dot println(b);
02:49 Save and Run.
02:59 As we can see, the output is True.
03:02 Let us see what happens if the value is less than 40.
03:07 Change weight to 30.
03:12 Save and run.
03:20 We can see that the output is False as expected.
03:24 This way, the greater than symbol is used to check if one value is greater than the other.
03:30 Similarly, less than symbol is used to check if one value is less than the other.
03:37 Let us change the greater than to less than symbol.
03:43 So, We are checking if the value of weight is less than 40.
03:48 Save, Run.
03:56 As we can see, the output is true as expected.
04:01 Let us change the value of weight to 45 and see the output.
04:09 Save and Run.
04:16 We see that we get a false because the condition
04:21 weight less than 40 is not true.
04:25 Now let us see how to check if a value is equal to another.
04:31 To do that, we use two equal to symbols.
04:35 Change less than symbol to double equal to.
04:41 Save and Run.
04:48 As we can see, the output is false because the value of weight is not equal to 40.
04:55 Now let us change the weight to 40 and see the output.
05:01 Save and Run.
05:08 As we can see, the output is True.
05:12 This way, double equal to is used for checking equality.
05:16 Please be careful because, often people use a single equal to symbol for checking equality.
05:22 And this gives unnecessary errors.
05:26 Next we'll see how to check for less than or equal to.
05:30 To do that, we will use a less than symbol followed by an equal to symbol.
05:35 Change the double equal to, to less than equal to.
05:42 Save and Run.
05:50 The output is True as expected.
05:53 Now let us change the value of weight to see if the less than check is performed.
05:59 Change 40 to 30.
06:04 Save and Run.
06:14 We see, that although the weight is not equal to 40 we get the output as True because it is less than 40.
06:22 Let us see what happens if the value of weight is greater than 40.
06:27 Let's say 50. Save and Run.
06:39 As we can see, the output is False because the value of weight is not equal to 40.
06:44 And it also not less than 40.
06:48 Similarly, we use a greater than symbol followed by an equal to symbol for checking greater than or equal to.
06:55 Let us try it.
06:57 Change less than equal to to greater than equal to.
07:04 Save and Run.
07:10 As we can see, the output is true because weight is greater than 40.
07:16 Let us change weight to a value less than 40. Let's say 30.
07:25 Save and Run.
07:32 We get a false because the value of weight is not greater than 40 and also not equal to 40.
07:39 Next, we’ll see how to check for not equal to.
07:46 It is done by using an exclamation mark followed by an equal to symbol.
07:53 Change greater than to exclamation.
07:59 So, this statement says: check if the value of weight is not equal to 40 and store the result in b.
08:08 Save and Run.
08:16 As we can see, the output is true because the values of weight is not equal to 40.
08:23 Let us change the weight to 40 and see the output.
08:28 Change 30 to 40.
08:31 Save, Run.
08:38 We get a false because the condition weight not equal to 40 is false.
08:45 The not equal to condition can be thought of as opposite of equal to condition.
08:50 This is how we use the various relational operators to compare data in Java.
08:58 This brings us to the end of this tutorial.
09:01 In this tutorial we have learnt about: the boolean data type,
09:06 the relational operators and
09:08 how to use relational operators to compare data.
09:13 As an assignment for this tutorial, find out if the two expressions shown are equivalent.
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Contributors and Content Editors

Gaurav, PoojaMoolya, Ranjana, Sandhya.np14, Sneha