Java/C2/Primitive-type-conversions/English-timed

From Script | Spoken-Tutorial
Revision as of 11:27, 8 August 2013 by Priyacst (Talk | contribs)

Jump to: navigation, search
Time' Narration
00:01 Welcome to the spoken tutorial on Type Conversion in Java.
00:06 In this tutorial, we learn:
00:08 * How to convert data from one data type to another.
00:13 * the two types of conversion, namely implicit and explicit conversion. And
00:18 * How to convert strings to numbers


00:23 For this tutorial we are using
  • Ubuntu 11.10
  • JDK 1.6 and
  • Eclipse 3.7


00:33 To follow this tutorial, you must have knowledge of data types in Java.


00:38 If not, for relevant tutorial please visit our website as shown
00:47 Type conversion means converting data from one data type to another.


00:53 Let us see how it it done.


00:55 Switch to Eclipse
01:02 Here we have the Eclipse IDE and the skeleton required for the rest of the code.


01:07 I have created a class TypeConversion and added the main method to it.


01:13 Now let us create a few variables.
01:19 int a equal to 5

float b

b equal to a


01:33 I have created two variables. a which is an integer and b which is a float.


01:39 I’m storing the integer value in a float variable.


01:43 Let us see what the float variable now contains.


01:48 System dot out dot println b '


01:58 Save the file and run it.
02:07 We can see that the integer 5 has been converted to float 5.0


02:13 This type of conversion is called implicit conversion.


02:17 As the name goes, the value is automatically converted to suit the data type.


02:24 Now let us convert float to an int, using the same method.
02:30 Remove the 5 float b equal to 2.5f and let us store b in a and print the value of a .
02:50 Save the file.


02:56 we see that there is an error.


03:00 The error message reads, Type mismatch: cannot convert from float to int


03:06 It means Implicit conversion is possible only from an int to a float but not the the other way.


03:13 To convert a float to an int we have to use explicit conversion.


03:17 Let us see how to do so.
03:23 We do that by using an int in parentheses, before the variable


03:34 This statement says the data in the variable b has to be converted to int data type and stored in a.
03:43 save and run the file
03:51 As we can see, the float value has been converted to int.


03:56 But to suit the data type, the data has been changed accordingly.


04:01 Explicit conversion can also be used to convert data from int to float.


04:07 Let us try the previous example.
04:10 int a =5, float b, b = float a
04:32 System.out.println(b);
04:36 We are using Explicit conversion to convert integer to a float
04:42 Save the file and Run it.


04:51 we see that the int value has been converted to a float value


04:58 Let us see what happens when we convert a character to an integer.
05:06 int a, char c equal to in single quotes 'm';

'

05:24 a equal to '(int) c
05:32 System dot out dot println ' a.
05:36 We are converting the character m to an integer and printing the value
05:43 Let us save and run it
05:53 As we can see, the output is 109 which the ascii value of m.


05:58 It means when a char is converted to int, its ascii value is stored.


06:03 Let us try this with a digit.
06:06 char c = digit 5
06:11 Save it and run it
06:18 As we can see, the output is 53 which is the ascii value of the character ‘5’
06:24 It is not the number 5.


06:26 To get the number, we have to use a string and convert it to an integer.


06:31 Now let us see how to do so.
06:33 Clean up the main function
06:38 type


06:40 String sHeight string form of Height equal to in double quotes 6


06:58 int h equal to explicit conversion to int of sHeight and
07:11 System dot out dot println h Save the file.
07:27 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


07:37 And the error message reads Cannot cast from String to int.


07:42 This means for converting strings, we cannot use implicit or explicit conversion.


07:48 It must be done by other methods. let us use them
07:58 Remove int sHeight and type Integer dot parseInt sHeight '.
08:21 Save the file and run it


08:29 we see that the value has been successfully converted to an integer.
08:35 To do this we use the parseInt method of the integer module.
08:41 Now let us see what happens if their are more than one digits like 6543
08:49 Save the file and run it


08:55 We see that again the string containing the number has been successfully converted to an integer
09:03 Now let us see what happens if the strings is a floating point number
09:10 Change 6543 to65.43.So we have a floating point number in the strings and we are converting it to an integer
09:22 Save the file run it.


09:31 We see that their is an error This happens beacuse we cannot convert a string which contains floating point number to an integer


09:41 We have to convert it to a float.Let us see how to do so;
09:45 First data type should be float,
09:51 Second we will use float . parsefloat
10:07 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.
10:18 Save the file run it. We can see that the string containing a floating point number has been successfully converted to floating point number.
10:33 And this is how we do implicit and explicit conversion and How do we converts strings to numbers.
10:45 This brings us to the end of the tutorial.
10:48 In this tutorial we have learnt how to convert data from one type to another.
10:54 What is meant by implicit and explicit conversin
10:57 and How to convert strings to numbers.
11:01 As an assignment for this tutorial Read about the Integer.toString and Float.toString.


11:07 And Find out What do they do?
11:14 To know more about the Spoken Tutorial project, watch the video available at the following link,
11:20 It summarises the spoken- tutorial project.
11:23 if you do not have good bandwidth, you can download and watch it
11:27 The Spoken Tutorial Project Team. Conducts workshops using spoken tutorials
11:31 Gives certificates for those who pass an online test.
11:34 For more details, please write to contact AT spoken HYPHEN tutorial DOT org.
11:40 The Spoken Tutorial Project is a part of the Talk to a Teacher project
11:44 It is supported by theNational Mission on Education through ICT, MHRD, Government of India.
11:50 More information on this Mission is available at the following link spoken HYPHEN tutorial DOT org SLASH NMEICT HYPHEN Intro
11:55 This tutorial has been contributed by TalentSprint. Thanks for joining.



Contributors and Content Editors

Gaurav, Kavita salve, PoojaMoolya, Priyacst, Sandhya.np14, Sneha