Variables
- Variables are nothing but reserved memory locations to store values. This means that when you create a variable you reserve some space in the memory.
- During program execution we can modify that data.
The data stored in the memory of the computer can be of many types. Example: integer, Decimal numbers, String etc. A Variable has TYPE, NAME and VALUE.
Syntax for Declaring a Variable
In the below example int is the type, a is the name, 10 is the value.
Syntax : Variable Declaration
int a = 10;
Addition of Two Numbers
Step 1) Declare two variables, say a and b as integer, assign values.
Step 2) Print addition of two numbers.
Example:Addition of two numbers
public class Demo{ public static void main (String[] args) { int a=10; int b=20; System.out.println(a+b); } }Try it Yourself
Exercise: Find the output of the following program.
10740.
Find the output of the code: public class Demo{ public static void main (String[] args){ int a=10; System.out.println(a+a+a); } }
20
30
40
10
Rules to declare a Variable
Rule | Correct | Incorrect |
---|---|---|
No space are allowed in the variable declarations. | int var a=10; | |
Except underscore ( _ ) no special symbol are allowed in the middle of variable declaration. | int var_1=10; | int "var"_1=10; int var-1=10; |
No keywords should access variable name. | int int=5; int main= 5; |
Assigning Value to Variable
Example:Multiply two numbers
public class Demo{ public static void main (String[] args) { int a=5,b=10,c; c=a*b; System.out.println(c); } }Try it Yourself
Exercise Q&A
14278.Find the output of the code:
public class Demo{ public static void main (String[] args){ int a=5,b=10,temp; temp=a; a=b; b=temp; System.out.println(a+" " +b); } }
10 10
5 5
10 5
5 10
14281.Find the output of the code:
public class Demo{ public static void main (String[] args){ int a=5; int b=a*10; System.out.println(b); } }
20
20
40
50