![]() ![]() If you have noticed, String is not primary / primitive data type in java. – array, class, interface and enum are non-primitive data types. short, byte, int, long, float, double, boolean and char. There are 8 primitive data types in java i.e. How many types of datatypes are there in java? We will understand more about data types in our next articleħ. Java has two types of datatype primitive and non-primitive data type. So, it is mandatory to use datatype before variable name and Java Compiler will cry, if you miss to do that. If we do not specify datatype, JVM can not decide how much space is required by that variable during program execution. In other words, data types are used by JVM to assign space for that variable in the memory. So, we need to declare a datatype of our variable accordingly. Storing a small number requires less space compared to large number. For example, Our two wheeler may require two blocks where as Car may require 6 blocks of space. How much memory a variable takes is depends on its datatype.įor Example, As we see in our daily life, Different types of vehicle requires different amount of space in your parking area. Every java variable takes up a certain amount of space in memory. Why is Specifying DataType Mandatory in Java?ĭata type of a variable is an attribute which tells what kind of data that variable can have. Yes, we can declare and initialize a variable together. Can we declare and initialize a variable together? For example, variable number is initialized with value 10 on line 9 in first code snippet.ĥ. Before initialization objects have nullvalue and primitive types have default values such as 0 or false. When we assign a value to a variable first time, it is known as variable initialization. ![]() What is variable Initialization? How is it different than Assignment? We can assign a value to variable any number of time in java, but when we assign a new value to a variable old value will be overwritten.įor example, in first code snippet, we have first assigned a value 10 to number and then modified its value by performing number+20 operation and assign it back to variable number by. We use assign operator (=) to assign a value to a variable. Jump to the question Why is Specifying DataType before variable name Mandatory? Before reading or assigning a value, that variable must have been declared. It is used by compiler to help programmer avoid any mistakes such as storing String values to integer variables. Java is known as strictly typed language as it is mandatory to specify a data type of a variable before variable name. Here number, flag and name are variable name and int, boolean and String are their respective data types. intīelow code snippet shows some more example of variable declaration. But along with that we have also specified its datatype i.e. If you have noticed in above example, we have declared variable number on line 6. modify variable value and assign it againĭeclaring a variable is very easy. initialization / assign a value to variable We will refer below code snippet multiple time to understand variable declaration, assignment and initialization in detail in subsequent topics. Here 'vary' word represent variation, it means we can change the value of a variable during program execution.įor Example, in below code snippet, we have declared a variable number, then in next step we initialized its value and then we modified its value. Variable value can be changed during program execution. Variable is also known as a container (or box) which is used to store data value during program execution in memory. Variable is a name which is given to a memory cell. I have discussed each and everything in very depth.
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