Difference between revisions of "Java/C2/Primitive-type-conversions/English-timed"

|| ''Time'''

|  Welcome to the '''spoken tutorial''' on '''Type Conversion in Java'''.

|   In this tutorial, we learn:

|* '''How to''' '''convert data from one data type to another'''.

|* the two types of conversion, namely '''implicit and explicit conversion.''' And

|* '''How to convert strings to numbers'''

 

 

|  For this tutorial we are using  

 

* '''Ubuntu 11.10'''

* '''JDK 1.6'''  and

* '''Eclipse 3.7'''

 

 

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

 

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

|Switch to '''Eclipse'''

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

 

|I have created a class '''TypeConversion''' and added the main method to it.

 

| '''int a '''''equal to '''''5'''

 

'''float b'''

 

'''b '''''equal to''''' a'''

 

|I have created two variables. '''a''' which is and integer and '''b''' which is a float.

 

|I’m storing the integer value in a float variable.

 

|'''System '''''dot''' ''out '''''dot '''''println '''''  '''''b '''' 

 

|Save the file and run it.

|  We can see that the integer '''5''' has been converted to float '''5.0'''

 

|Now let us convert float to an int, using the same method.

| | Remove the ''' 5'''  float b equal to 2.5f  and let us store '''b''' in a and print the value of a .  

| we   see that there is an error.

 

|The error message  reads, '''Type mismatch: cannot convert from float to int'''

 

|To convert a '''float '''to an  '''int''' we have to use explicit conversion.

 

| We do that by using an '''int''' in parentheses, before the variable

 

| This statement says the data in the variable '''b''' has to be converted to '''int''' data type and stored in a.

|   save and run the file  

| Explicit conversion can also be used to convert data from int to float.

 

| Let us try the previous example.

|  int a =5, float b, b = float a

| We are using Explicit conversion to convert integer to a ''' float'''

| Save  the file and Run it.

 

|  we see that   the int value has been converted to a '''float''' value  

 

| Let us  see what happens when we convert a '''character''' to an '''integer'''.

| int a,  '''char c '''''equal to in single quotes ''''''m';'''

 

| '''a '''''equal to  ''''(int) c '''''  

| '''System '''''dot '''''out '''''dot '''''println '''' '''''a.'''

| We are converting the character ''' m''' to an integer and printing the value

| Let us save and run it  

|  As we can see, the output is 109 which the ascii value of '''m'''.  

 

|  char c = digit 5   

|  Save it and run it  

|  As we can see, the output is 53 which is the ascii value of the character ‘5’

| To get the number, we have to use a string and convert it to an integer.

 

|  Clean up the main function  

| type

 

|'''String sHeight ''''' string form of Height equal to in double quotes '''''6 '''''

 

   

|'''int h '''equal to '''explicit conversion''' to  '''int of sHeight '''  and  

|'''System '''''dot''''' out '''''dot '''''println '''''  '''''h ''''' Save the file.  

|I’ve created a string variable with value 6 and i am trying to convert it to an integer but we see that their is an error

 

 

|  And the error message reads '''Cannot cast from String to int.'''  

 

|This means for converting strings, we cannot use implicit or explicit conversion.

 

|It must be done by other methods. let us use them

|  Remove  '''int sHeight ''' and type  '''''Integer '''''dot '''''parseInt  sHeight ''''.

|Save the file and run it  

 

 

|  we   see that the   value has   been successfully converted to an integer.

|To do this we use the''' parseInt method '''of the integer module.  

|Now let us see what happens if their are more than one digits like '''6543'''

| Save the file and run it

 

|  We see that again the string containing  the number has been successfully converted to an integer

|Now let us see what happens if the strings is a floating point number

|Change''' 6543 to65.43'''.So we have a floating point number in the strings and we are converting it to an integer

|Save the file run it.

|  We see that their is an error This happens beacuse we cannot convert a  string  which contains   floating point number to an integer

 

| We have to convert it to  a float.Let us see how to do so;

|First data type should be float,

|Second we will use ''' float . parsefloat'''

|We are using the Parsefloat methods of the float class to convert the string containing a floating point number into an actual floating point number.

|Save the file   run it. We can  see that the string containing a floating point number  has been successfully converted  to floating point number.

|And this is how we do '''implicit and explicit conversion and How do we converts strings to numbers'''.

|   This brings us to  the end of the tutorial.  

|In this tutorial we have learnt how to convert '''data from one type to another'''.  

| What is meant by implicit and  explicit conversin

|  |As an assignment for this tutorial Read about the '''Integer.toString''' and '''Float.toString. '''

 

|And Find out What do they do?

| To know more about the '''Spoken Tutorial''' project, watch the video available at the following link,

| It  summarises the spoken- tutorial project.

|if you do not have good bandwidth, you can download and watch it

| The Spoken Tutorial Project Team. Conducts workshops using '''spoken tutorials'''

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|The   '''Spoken Tutorial '''Project is a part of the '''Talk to a Teacher''' project   

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