Difference between revisions of "Java/C2/Relational-Operations/English-timed"

|   Welcome to the spoken tutorial on '''Relational Operators in Java'''.

| '''the boolean data type'''

| '''Relational operators '''and

|  how to '''compare data '''using '''Relational operators.'''

 

|  For this tutorial we are using  

 

'''Ubuntu 11.10''',  

 

|  To follow this tutorial, you must have knowledge of '''data types '''in''' Java'''

 

|  If not, for relevant tutorials, please visit our  website   as shown.

| Relational operators are used to check for conditions.

 

 

| Their output is a variable of boolean data type

 

|  A  boolean data type is of size  1 bit   

 

|  '''True '''or '''False. '''

 

|  '''True''' is the output when the condition is true.

 

|  '''False''' is the output if the condition is not true.  

|  Here is a list of the Relational operators available.

 

| * greater than

| * less than

| 01:13 

| 00:14

| * greater than or equal to

|  * less than or equal to

| * not equal to

| We shall look into each of them in detail.

| Switch to Eclipse.

|   Here we have the '''Eclipse IDE '''and the skeleton required for the rest of the code.

 

| I have created a class '''BooleanDemo''' and added the '''Main''' method.

 

| Now let us add some expressions.

|  Type '''boolean b ; '''

 

|  We shall store the result of our condition in b.

|  We shall define a variable weight and check for a condition using that variable.

 

|  '''int weight '''''equal to '''''45;'''

 

|  We shall check if the value in weight is greater than '''40.'''

 

|  '''b '''''equal to '''''weight '''''greater than '''''40;'''

 

|  This statement says check if the value of variable is greater than 40 and store the result in b;

 

|  Now Let us print the value of b.

 

|  '''System '''''dot '''''out '''''dot '''''println(b);'''

 

|  Let us see what   happens if the value is less than 40.

 

|  Change weight to 30.

 

|  Save and run

|   03:20

|  We can see that the output is False as expected.

|  This way, the''''' '''greater than'' symbol is used to check if one value is ''greater than'' the other.

 

| 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.''

 

|   So We are checking if the value of '''weight''' is less than '''40'''.

 

|   '''Save''' '''Run'''   

| 03:56

| As we can see, the output is '''True '''as expected.

 

|  Let us change the value of weight to 45 and see the output.

 

|  Save and Run.

|  We see that we get a False because the condition,

 

|  '''weight''''' less than '''''40''' is not true.

 

|  To do that, we use '''two equal to symbols.'''

 

|  change ''less than ''symbol'' ''to ''double equal to.''

 

|  '''Save''' and '''Run'''   

|  As we can see, the output is '''False '''because the value of weight is not equal to 40'''.'''

|  Now let us change the weight to 40 and see the output.

|  Save and  Run.

|  As we can see, the output is True

 

|  This way, Double equal to is used for checking equality.

 

|  And this gives unnecessary errors.

|   change the double equal to to less than equal to.

 

|   the output is '''True''' as expected.

 

|  Now let us change the value of weight to see if the '''less than''' check is performed.

|  We see, that although the weight is not equal to 40 we get the output as '''True''' because it is less than 40.

 

|  Let us see what happens if the value of weight is greater than 40.

|  06:274

|  Let say 50. Save and Run.

|As we can see, the output is False  because the value of weight is not equal to 40.

 

|  Similarly we use a greater than symbol followed by an equal to symbol for checking '''greater than''' or''' equal to'''.

 

|  Change ''less than equal to'' to ''greater than equal to''

 

|  Save and Run.

 

|  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. Lets say 30.

 

|  Save and Run.

|  We get a false because the value of weight is not greater than 40 and also not equal to 40.

| Next, we’ll see how to check for '''not equal to'''

 

|  Change ''greater than'' to ''exclamation ''

 

|  So this statement says check if the value of '''weight''' is not equal to '''40''' and store the result in '''b'''

 

|  '''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.

| Change 30to 40.

| Save. Run.

|   We get a '''false''' because the condition weight not equal to 40 is false.

| The not equal to condition can be thought of as opposite of equal to condition.

| 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.  

 

| In this tutorial we have learnt,  about the boolean data type

|  The relational operators and

|  how to use '''relational operators''' to '''compare''' two values

|   09:13

| As an assignment for this tutorial, find out if the two expressions shown are equivalent?

 

 

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|   09:36

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|   09: 50

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