What is Variables and Datatype?

What is Variables?

Variables are containers for storing data values.

1. String – stores text, such as “Hello”. String values are surrounded by double quotes
2. int – stores integers (whole numbers), without decimals, such as 123 or -123
3. float – stores floating point numbers, with decimals, such as 19.99 or -19.99
4. char – stores single characters, such as ‘a’ or ‘B’. Char values are surrounded by single quotes
5. boolean – stores values with two states: true or false

What is Datatypes ?

As explained in the previous chapter, a variable in Java must be a specified data type:

Data Type Description

byte Stores whole numbers from -128 to 127

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
       9,223,372,036,854,775,807
       9,223,372,036,854,775,807

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float Stores fractional numbers. Sufficient for storing 6 to 7

       decimal digits
       decimal digits
       decimal digits

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double Stores fractional numbers. Sufficient for storing 15 to 16

       decimal digits
       decimal digits
       decimal digits

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boolean Stores true or false values

char Stores a single character/letter or ASCII values

原文链接：What is Variables and Datatype?