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#Do-while #loop You can understand Do-while loop only 5 minutes ||Loop c...





Do-while loop concepts it's very useful for the programmer the interview room so many questions ask through the interview



Java do while loop is used to execute a block of statements continuously until the given condition is true. do while loop in Java is similar to while loop except that the condition is checked after the statements are executed, so do while loop guarantees the loop execution at least once.

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1 Java do while loop
1.1 do while java flow diagram
1.2 Java do while loop example
1.3 do while true java
1.4 do while vs while loop
Java do while loop
Java do while loop syntax is as follows:


do {
// statements
} while (expression);
The expression for the do-while loop must return a boolean value, otherwise, it will throw compile time error.

do while java flow diagram
Java Do While Loop
Java Do While Loop

Java do while loop example
Here is a simple java do while loop example to print numbers from 5 to 10.



package com.journaldev.javadowhileloop;

public class JavaDoWhileLoop {

public static void main(String[] args) {

int i = 5;
do {
System.out.println(i);
i++;
} while (i <= 10);
}
}
java do while loop example

do while true java
We can create an infinite loop by passing boolean expression as true in the do while loop.


Here is a simple do while java infinite loop example.


package com.journaldev.javadowhileloop;

public class DoWhileTrueJava {

public static void main(String[] args) throws InterruptedException {
do {
System.out.println("Start Processing inside do while loop");
// look for a file at specific directory
// if found, then process it, such as inserting rows into database
System.out.println("End Processing of do while loop");

Thread.sleep(5 * 1000);
} while (true);
}
}
Note that you will have to manually quit the application to stop it, using Ctrl+C if program is executed in terminal. If you have executed program in Eclipse IDE then there is a red color button to terminate the program.

do while vs while loop
The only time you should use do while loop is when you want to execute the statements inside loop at least once, even though condition expression returns false. Otherwise it’s always better to use while loop.

Java while loop looks more cleaner than do while loop.

That’s all for java do while loop. You should also look into java for loop and java continue statement.

Reference: Oracle Documentation



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Pankaj
I love Open Source technologies and writing about my experience about them is my passion.

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Comments

rupesh
says:
February 25, 2019 at 6:04 am
please give syntax for do while loop

Reply


Nikhil
says:
February 6, 2019 at 6:56 pm
hi Pankaj,

Can you please correct the “if condition is true arrow” in the image?

Reply

Pankaj
says:
February 6, 2019 at 9:40 pm
Ah, thanks for noticing that small mistake. I have corrected the image now.

Reply
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