Learn phrases, commands, and blocks in Java (plain language)

In this tutorial, you will learn about expressions, statements, blocks, and the difference between a phrase and a commands

We used phrases, commands, and blocks in previous tutorials without going into too much detail about them. 

Now you know what variables, operators and literals are, so it will be easier to understand these concepts.

Java Expressions

Expressions include variables, operators, literals, and method calls that evaluate a single value.

Let’s give an example:

int score;

score = 90;

Here, score = 90 is the expression that returns int.

Double a = 2.2, b = 3.4, result;

result = a + b – 3.4;

Here, a + b is 3.4.

if (number1 == number2)

System.out.println (“Number 1 is larger than number 2”);

Here, number2 == number1 is the expression that boolean returns. Similarly, “Number 1 is larger than number 2” is a string expression.

Java Statements

Commands form a complete execution unit. For example,

int score = 9 * 5;

Here, 9 * 5 is a statement that returns 45, and int score = 9 * 5 is a command.

Phrases are part of commands.

Grammatical expressions

Some expressions can be used with; Terminated are known as commands. For example:

number = 10;

Here, number = 10 is a phrase and number = 10; Is a command that the compiler can execute.

++ number;

Here, ++ number is the expression while ++ number; Is a command.

Definitive commands

Defines commands that define variables. For example,

Double tax = 9.5;

The above command defines the tax variable with an initial value of 9.5.

There are also control flow commands used in decision making and loops in Java. You will learn control flow commands in later tutorials.

3- Java block

A block is a group of expressions (zero or more) enclosed in brackets}}. For example,

  1. class AssignmentOperator {
  2. public static void main (String [] args) {
  3. String band = “Beatles”;
  4. if (band == “Beatles”) {// start of block
  5. System.out.print (“Hey”);
  6. System.out.print (“Jude!”);
  7. } // end of block
  8. }
  9. }

Above are two phrases

System.out.print (“Hey”);

And

System.out.print (“Jude!”);

Inside the listed block.

A block may have no expression. Consider the following examples:

class AssignmentOperator {

public static void main (String [] args) {

if (10> 5) {// start of block

} // end of block

}

}

class AssignmentOperator {

public static void main (String [] args) {// start of block

} // end of block

}

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