In this tutorial you will learn about the Java Decision Making Statements and its application with practical example.
Java Decision Making Statements
There are case where we want a a block of code to be executed when some condition is satisfied. In Java, we have rich set of Decision Making Statement that enable computer to decide which block of code to be execute based on some conditional choices. Decision making statement statements is also referred to as selection statements. Decision making statement evaluates single or multiple test expressions which results is “TRUE” or “FALSE”. The outcome of the test expression/condition helps to determine which block of statement(s) to executed if the condition is “TRUE” or “FALSE” otherwise.
In Java, we have following decision making statements –
- Java if Statements
- Java If else Statements
- Java if else if Statements
- Java Nested If Statements
- Java Switch Case Statement
Java If Statement
If statement allows a block of code to be executed only when a specified condition is true. An if statement evaluates a boolean expression followed by one or more statements. The given boolean expression results in a boolean value that can only be either true or false.
Syntax:-
1 2 3 |
if(condition){ // statements } |
Here, Condition is a Boolean expression that results in either True or False, if it results in True then statements inside if body are executed, if it results in False then execution is skipped from if body.
Java If Else Statement
In Java, when we want to execute a block of code when if condition is true and another block of code when if condition is false, In such a case we use if…else statement.
Syntax:-
1 2 3 4 5 |
if(condition){ // statements } else { // statements } |
Here, Condition is a Boolean expression that results in either True or False, if it results in True then statements inside if body are executed, if it results in False then statements inside else body are executed.
Java If Else If Statement
When we want to add multiple condition checks in single if else statement then by using if else-if else statement we can easily add multiple conditions. In Java, if..else..if statement allows us add alternative set of test conditions in if..else statement using else-if and single else statements for if condition. In such way if..else..if statement is used to select one among several blocks of code to be executed.
Syntax:-
1 2 3 4 5 6 7 8 9 10 11 12 13 14 |
if(condition1) { // statement(s) } else if(condition2){ // statement(s) } . . else if(conditionN){ // statement(s) } else { // statement(s) } |
Java Nested If Statement
In Java, when there is an if statement inside another if statement then it is known as nested if else. Nested if else can also be simplified using Java Switch Case Statement.
Syntax:-
1 2 3 4 5 6 7 8 9 10 11 12 13 14 |
if(condition1) { if(condition2){ // statements } else { // statements } } else { if(condition3){ // statements } else { // statements } } |
Java Switch Case Statement
In Java, switch case statement is simplified form of the Java Nested if else statement , it helps to avoid long chain of if..else if..else statements. A switch case statement evaluates an expression against multiple cases in order to identify the block of code to be executed.
Syntax:-
1 2 3 4 5 6 7 8 9 10 11 |
switch(expression){ case value1: // statements break; case value2: // statements break; default: // statements break; } |