Difference between revisions of "Java/C2/do-while/English"

Welcome

Learning Outcomes

• the do-while loop and
• how to use it

Tools Used

Ubuntu 11.10,

JDK 1.6 and

Eclipse 3.7

Prerequisites

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http://spoken-tutorial.org

Point on slide

do-while loop

Notice that it is similar to a while loop.

It has two parts.

First is the loop running condition. And the second is the loop variable

And so the condition is checked after the execution of the statements inside the do block

Now let us see an example.

Minimize Slides and open Eclipse

Eclipse should contain the following code

public class DoWhileDemo{

public static void main(String[] args){

}

}

We have created a class DoWhileDemo and added the main method to it.

int n = 1;

do {

System.out.println(n);

n = n + 1;

} while(n <= 10);

Type

int n equalto 1 semicolon

n is going to be loop variable.

open curly braces and close

System.out.println(n);

We shall print the value of n and then increment it.

n equalto n plus 1;

n is less than or equal to 10

Outside the braces Type while in paranthesis(n less than equalto 10)

Save and Run.

Highlight print statement.

Highlight condition statement

And then, the condition is checked.

since it is true, again 2 is printed and n becomes 3.

And so on till all the 10 numbers are printed and the value of n becomes 11.

When n = 11, the condition fails and the loop stops.

Change n = 1 to n = 50.

Change n = n + 1 to n = n - 1

So Change the condition to n >= 40

Save and Run.

As we can see, the numbers from 50 to 40 are printed.

int n = 25;

Again Type

int n = 25;

We shall use x to store the square root of the number if it is a perfect square.

x = x + 1;

}

Open close braces.

Inside the bracesx equal to x plus 1

x = x + 1;

} while(x * x < n);

while in paranthesis (x into (star) x < n)

And Close the do-while with a semi-colon

Or x must be greater than n.

It is not equal to n, the number is not a perfect square.

System.out.println(x * x == n);

Let us try with other perfect square.

We again get a true.

Save and Run.

Point to output.

We get a false.

Now let us see what happens when the value of n is 0.

Let us run the code.

Save and Run.

x into x is less than n is checked, the value of x is incremented and it becomes 1

The loop condition fails and loop does not run.

Specially, when the loop must run at least once.

Slide 6

Summary

In this tutorial, we learnt about the

do-while loop and how to use it

Given a binary number, find out its decimal equivalent. Example: 11010 => 26

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