Expressions, Statements, and Blocks in java 7
In this section we will discuss expressions, Statements and Blocks in java 7. This is one type of Language Fundamentals.
Expressions :
An expression can be formed by combining literals, variables and operators. It is made according to the language syntax that evaluate some value. Usually it complete some work of your program. It is used in computing and assigning values to your variables and also very helpful to control your program flow.
Example :
Here some expressions example -
int number=10;
//number=10 is expression.
String test="Hello";//test="Hello" is expression.
System.out.println("Number = " + number); //"Number = " +
number is expression.
You can also create compound expressions with the help of other smaller expressions. It is necessary that data types of the smaller expressions matches with the compound statements.
x=(y*20) - (z/10); //unambiguous
For compound expression unambiguous recommended.
x=y*20 - z/10 ; //ambiguous
Statements :
When you write a complete expression with semicolon(;) it creates a
statement. You can say a statement is a complete unit of execution.
Assignment expressions, Any use of ++ or --, Method invocations, Object creation
expressions are used in foundation of a statements. Such kind of statements are
also said expression statements.
Example :
number= 100; //assignment statement
number++; //increment statement
System.out.println("Hello Roseindia!");// method invocation statement
Roseindia myRose = new Roseindia ();// object creation statement
Blocks :
When you group zero or more statements by using some balanced braces then it forms block. So you can say a block is a group of any number of statements.
Example :
if (some condition) { // begin block 1
System.out.println("Condition is true.");
} // end block one
else { // begin block 2
System.out.println("Condition is false.");
} // end block 2
Example : This example
class ExpressionStatementBlock {
public static void main(String[] args) {
int x = 10; // statement, x=10 is expression
int y = 20; // statement, y=20 is expression
if (x > y) {// begin block
System.out.println("x is greater than y."); // expression and statement.
}// end block
else {// begin block
System.out.println("y is greater than x."); // expression and statement.
}// end block
}
}
Output :
y is greater than x.