Hello Everyone,
I know that , The do...while statement will always execute the block of code once, it will then check the condition, and repeat the loop while the condition is true.
but when i am running this code
<?php
$num = 1;
do
{
$num++;
echo $num;
}
while ($num<=5)
?>why the ouput is 23456 anhd not 2345 ?
Because you have $num<=5 . It will run the loop again when $num = 5 , so you get $num++, making $num = 6.
To cut off at 5, take the "=" out of the while condition.
why it will run the loop again when $num = 5 according to condition ?
Well, walk through it step-by-step:
When $num = 1:
When $num = 2:
Let's skip to 4:
Therefore, since $num = 5 and the condition accepts all number up to and including 5, we will run the loop again:
When $num = 5:
Does it make sense now?
Ok, thanks
Hey..! but when i'm incrementing after printing the first value why the output is 12345 ?
i.e
<?php
$num = 1;
do
{
echo "The number is " . $num . "<br />";
$num++;
}
while ($num<=5);
?>Because $num starts at 1. If you echo before incrementing then the number hasn't changed to 2 yet. it changes to 2 at $num++
Why don't you take a notebook or slate and try it for every loop outputs?
I agree with rajarajan. When you first start programming it is very useful to grab a pen and a piece of paper and work through the changes in the variables' content step by step until you get the hang of it.
I've always found 'do-while' more difficult than just a 'while'
$num = 1;
while($num <= 5){
echo "The number is " . $num . "<br />";
$num++;
}Pre-process test (while) - check value before any code is run.
Post-process test (do-while) - check value after code is run.
I suppose it depends upon the implementation, but I've very rarely HAD to use do-while. Come to think of it, I can't remember the last time I used it.
We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.