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Computer Programming Java Data Types.pptx
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- 2. DATA TYPES AREDIVIDED INTO TWO GROUPS: •Primitive data types – includes byte, short, int, long, float, double, Boolean and char •Non-primitive data types – such as String, Arrays and Classes
- 3. PRIMITIVE DATA TYPES •Aprimitive data type specifies the type of a variable and the kind of values it can hold.
- 4. PRIMITIVE DATA TYPES •byte - Stores whole numbers from -128 to 127 • short - Stores whole numbers from -32,768 to 32,767 • int - Stores whole numbers from -2,147,483,648 to 2,147,483,647 • long - Stores whole numbers from - 9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
- 5. PRIMITIVE DATA TYPES •float - Stores fractional numbers. Sufficient for storing 6 to 7 decimal digits • double - Stores fractional numbers. Sufficient for storing 15 to 16 decimal digits • boolean - Stores true or false values • char - Stores a single character/letter or ASCII values
- 6. JAVA NUMBERS Primitive numbertypes are divided into two groups: • Integer types stores whole numbers, positive or negative (such as 123 or -456), without decimals. Valid types are byte, short, int and long. • Floating point types represents numbers with a fractional part, containing one or more decimals. There are two types: float and double.
- 7. INTEGER TYPES Byte • Thebyte data type can store whole numbers from -128 to 127. This can be used instead of int or other integer types to save memory when you are certain that the value will be within -128 and 127:
- 8. INTEGER TYPES Short • Theshort data type can store whole numbers from -32768 to 32767:
- 9. INTEGER TYPES Int • Theint data type can store whole numbers from - 2147483648 to 2147483647. In general, the int data type is the preferred data type when we create variables with a numeric value.
- 10. INTEGER TYPES Long • Thelong data type can store whole numbers from -9223372036854775808 to 9223372036854775807. This is used when int is not large enough to store the value. Note that you should end the value with an "L":
- 11. INTEGER TYPES Floating PointTypes • You should use a floating point type whenever you need a number with a decimal, such as 9.99 or 3.14515. • The float and double data types can store fractional numbers. Note that you should end the value with an "f" for floats and "d" for doubles:
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- 13. INTEGER TYPES Use floator double? • The precision of a floating point value indicates how many digits the value can have after the decimal point. The precision of float is only six or seven decimal digits, while double variables have a precision of about 16 digits. Therefore, it is safer to use double for most calculations.
- 14. INTEGER TYPES Scientific Numbers •A floating point number can also be a scientific number with an "e" to indicate the power of 10:
- 15. JAVA BOOLEAN DATATYPES Boolean Types • Very often in programming, you will need a data type that can only have one of two values, like: • YES / NO • ON / OFF • TRUE / FALSE
- 16. JAVA BOOLEAN DATATYPES Boolean values are mostly used for conditional testing.
- 17. JAVA CHARACTERS Characters • Thechar data type is used to store a single character. • The character must be surrounded by single quotes, like 'A' or 'c':
- 18. JAVA CHARACTERS Alternatively, ifyou are familiar with ASCII values, you can use those to display certain characters:
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- 23. JAVA CHARACTERS Strings • TheString data type is used to store a sequence of characters (text). String values must be surrounded by double quotes:
- 24. JAVA CHARACTERS • TheString type is so much used and integrated in Java, that some call it "the special ninth type". • A String in Java is actually a non- primitive data type, because it refers to an object. The String object has methods that are used to perform certain operations on strings.
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- 26. NON-PRIMITIVE DATA TYPES •Non-primitive data types are called reference types because they refer to objects. The main differences between primitive and non-primitive data types are: •Primitive types in Java are predefined and built into the language, while non-primitive types are created by the programmer (except for String).
- 27. NON-PRIMITIVE DATA TYPES •Non-primitivetypes can be used to call methods to perform certain operations, whereas primitive types cannot. •Primitive types start with a lowercase letter (like int), while non-primitive types typically starts with an uppercase letter (like String). •Primitive types always hold a value, whereas non-primitive types can be null. Examples of non-primitive types are Strings, Arrays, Classes etc.
- 29. 1. What isan int in Java? A. A data type representing integers. B. A data type representing strings. C. A data type representing decimals.
- 30. 2. Add thecorrect data type for the following variables:
- 31. 3. byte, short,int, long, float, double, boolean and char are called:
- 32. 4. Integer typesare used to store: A. Floating point numbers B. Decimals C. Whole numbers
- 33. 5.Which is NOTa valid integer type? A. byte B. size C. short D. double E. int
- 34. 6. True orFalse: A float variable has greater precision than double.
- 35. 7. What isthe correct letter suffix to use for float values? A. a B. b C. c D. d E. f
- 36. 8. What isthe correct syntax for declaring a boolean variable in Java? A. boolean isJavaFun = ‘true’; B. boolean isJavaFun = true; C. bool isJavaFun = true; D. boolean isJavaFun = 1;
- 37. 9. The booleandata type can take two values, which are: A. true and false B. truth and falsy C. 1 and 0
- 38. 10. What isthe output of the following code? boolean isFishTasty = false; System.out.println(isFishTasty); A.true B.false C.1 D.0
- 39. 11. Which datatype is used to store a single character? A. char B. String C. int D. single
- 40. 12. The characterinside a char variable must be surrounded by: A. Single quotes B. Double quotes C. Question marks
- 41. 13. What isthe output of the following code? char myLetter = 'B'; System.out.println(myLetter); A.‘B’ B. B C. myLetter D. b
- 42. 14. To storemore than one character (a text), you must use: A. The string data type. B. The String data type. C. The text data type. D. The char data type.
- 43. 15. What isthe output of the following code? String name = "John Doe"; System.out.println(name); A. John Doe B. name
Editor's Notes
- #2 As explained in the previous chapter, a variable in Java must be a specified data type: int (integer – whole number), Float (floating point number), char (character), Boolean, String
- #3 There are eight primitive data types in Java:
- #6 Even though there are many numeric types in Java, the most used for numbers are int (for whole numbers) and double (for floating point numbers).
- #11 float - Stores fractional numbers. Sufficient for storing 6 to 7 decimal digits double - Stores fractional numbers. Sufficient for storing 15 to 16 decimal digits
- #25 Here's a real-life example of using different data types, to calculate and output the total cost of a number of items:
- #29 A.
- #30 Int, float, char, Boolean, String
- #31 primitive
- #32 C
- #33 B
- #34 False
- #35 E
- #36 b
- #37 A
- #38 false
- #39 A
- #40 A
- #41 B
- #42 B
- #43 A