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

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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 tutorials, 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 is 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 meaning string form of Height equal to in double quotes 6
06:58 int h equal to explicit conversion 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 there 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 there 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 string is a floating point number.
09:10 Change "6543" to "65.43". So, we have a floating point number in the string and we are converting it to an integer.
09:22 Save the file, run it.
09:31 We see that there is an error. This happens because we cannot convert a string which contains floating point number into 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 a floating point number.
10:33 And this is how we do implicit and explicit conversion and how we convert 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 conversion.
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 summarizes the Spoken Tutorial project.
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11:40 The 'Spoken Tutorial' Project is a part of the 'Talk to a Teacher' project.
11:44 It is supported by the National 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