I have this code written but I am having little issue or might be I am missing something,
public function test()
{
$number = "8192";
for ($i=1; $i<=32; $i++)
{
if(($number % pow(2,$i)) == 0)
{
$final = 32-$i;
echo $final;
}
}
exit;
}
I need to get which Exponent aka $i is used and then need to minus the value from 32 (or something else) to get the final results.
Since you want to compare the values just change the if condition, the modulus operator will not give you the exact result,
Here is the complete answer :
public function test()
{
$number = "8192";
for ($i=1; $i<=32; $i++)
{
if($number == pow(2,$i))
{
$final = 32-$i;
echo $final;
break;
}
}
exit;
}
Related
I had a need to generate a list of four-digit numbers for use as codes. The digits should not repeat, and each next digit should not be sequential. There were some questions that were similar but not enough for me to answer. I chose to share my function instead. It did not matter if reverse numbers were in the list e.g. 1357 > 7531.
It occurred to me that it there may be an opportunity for a recursive function, possibly to return five or six-digit numbers. Improvements to my function are most welcome.
public function codeList() {
$data = [];
for ($ii=0; $ii < 10; $ii++) {
for ($jj=0; $jj < 10; $jj++) {
for ($kk=0; $kk < 10; $kk++) {
for ($ll=0; $ll < 10; $ll++) {
$str = "{$ii}{$jj}{$kk}{$ll}";
$arr = str_split($str);
if (count($arr) === count(array_unique($arr))) {
if (($arr[0] + 1 != $arr[1]) && ($arr[1] + 1 != $arr[2]) && ($arr[2] + 1 != $arr[3])) {
$data[] = $str;
}
}
}
}
}
}
return $data;
} # END FUNCTION codeList
I am trying to make a simple while loop using a class to get the factorial of a number. However, for some reason, the while loop is only returning the value after it has run once.
Here is my code:
<?php
class Factorial {
public function calculate($int){
$intStep = $int-1;
do {
$int*=$intStep;
$int--;
return $int;
} while($int>0);
if (!is_int($int)){
echo "entry is not a number";
}
}
}
$factorial = new Factorial;
echo $factorial->calculate(5);
I see a number of problems with your code:
return $int; is run inside the do while loop, which means it'll only ever run once.
You're decrementing $int instead of $intStep
You're checking if $int is below zero instead of $intStep
Here's your code with all of these problems fixed, it works and returns 15:
class Factorial {
public function calculate ($int) {
if (!is_int($int)) {
echo "entry is not a number";
}
$intStep = $int - 1;
do {
$int += $intStep;
$intStep--;
} while ($intStep > 0);
return $int;
}
}
$factorial = new Factorial;
echo $factorial->calculate(5);
3v4l.org demo
You shouldn't return from your function until your result is ready. Since you return early, you won't finish your calculation.
In general, your life will be easier if you learn how to debug. For PHP, the easiest way would be to echo stuff throughout your code. If you put echo $int inside of your loop it would be more obvious to you what the issue was.
try this
<?php
class Factorial {
public function calculate($num){
$Factorial = 1;
$i =1;
do{
$Factorial *= $i;
$i++;
}while($i<=$num);
return $Factorial;
}
}
$factorial = new Factorial;
echo $factorial->calculate(5);
?>
Factorial ? Maybe the following code is what you want:
Don't forget negative Numbers.
class Factorial {
public function calculate ($int) {
if (!is_int($int)) {
echo "entry is not a number";
}
if ($int == 0 || $int == 1) {
$result = 1;
} else if ($int < 0) {
$result = $this->calculate($int + 1) * $int;
} else {
$result = $this->calculate($int - 1) * $int;
}
return $result;
}
}
$factorial = new Factorial;
echo $factorial->calculate(-4);
I am trying to write prefixed unique coupon code for get the chance to be a intern at one company. It went well so far, my code is generating 250st, 10 length of codes every time I refresh the page. However, I am issuing a problem with prefixed part. Normally coupon code is looking like this, just one example "1SC476XY3B" but I want every code to start "AB" and then 8 length of code so total will be 10. Can you help me guys? All help will be appreciated, thanks.
<?php
function unique_coupon_codes($number_of_codes,$exclude_codes_array='',$code_length = 10)
{
$characters = "0123456789QWERTYUIOPASDFGHJKLZXCVBNM";
$unique_codes = array();
for($j = 1 ; $j <= $number_of_codes; $j++)
{
$code = "";
for ($i = 1; $i <= $code_length; $i++)
{
$code .= $characters[mt_rand(0, strlen($characters)-1)];
}
if(!in_array($code,$unique_codes))
{
if(is_array($exclude_codes_array))
{
if(!in_array($code,$exclude_codes_array))
{
$unique_codes[$j] = $code;
}
else
{
$j--;
}
}
else
{
$unique_codes[$j] = $code;
}
}
else
{
$j--;
}
}
return $unique_codes;
}
echo '<h1>Unique Coupon Codes</h1>';
echo '<pre>';
print_r(unique_coupon_codes(250,'',10));
echo '</pre>';
It needs a minor change while initializing $code variable. Change $code = ""; to $code = "AB"; And call unique_coupon_codes function as
print_r(unique_coupon_codes(250, '', 8));
Here generate a unique code of 8 digits as you already have prefix AB of length 2 characters.
How about something like this? :-)
function unique_coupon_codes($number_of_codes,$exclude_codes_array=[],$code_length = 10, $code_prefix="") {
$characters="0123456789QWERTYUIOPASDFGHJKLZXCVBNM";
$unique_codes = array();
for($i=1;$i<=$number_of_codes;$i++) {
$code="";
for($o=1;$o<=$code_length;$o++) {
$code .= $characters[mt_rand(0, strlen($characters)-1)];
}
if(in_array($code, $unique_codes) || in_array($code, $exclude_codes_array)) {
$i--;
} else {
$unique_codes[$i] = $code_prefix.$code;
}
}
return $unique_codes;
}
echo '<h1>Unique Coupon Codes</h1>';
echo '<pre>';
print_r(unique_coupon_codes(250,'',8, 'AB'));
echo '</pre>';
I am building a function that would receive 2 params, a string and a number.
it would basically print the first letters $n of $s.
I need to run a loop, please don't advise other non looping methods.
And yes, I need to keep the loop true throughout the function, it's suppose to close when the if is met.
For some reason the loop isn't closing, even though there's a return in the if condition that is being met when $stringCounter equals $n (=10 in this example.)
function printCounter($s, $n)
{
$stringCaller = '';
$stringCounter = strlen($stringCaller);
while (1) {
$stringCaller .= $s;
if ($stringCounter == $n) {
return $stringCaller;
}
}
}
printCounter('aba', '10');
You should imove the calc of $stringCounter inside the loop otherwise this never change
$stringCaller = '';
while (1) {
$stringCounter = strlen($stringCaller);
$stringCaller .= $s;
if ($stringCounter >= $n) {
return $stringCaller;
}
}
On my oppinion, TS is searching next approach:
function printCounter($s, $n)
{
$result = '';
$str_lenght = strlen($s);
if(!$str_lenght) {
return $result;
}
while (true) {
$result .= $s;
$result_lenght = strlen($result);
if($result_lenght/$str_lenght >= $n) {
return $result_lenght;
}
}
}
echo printCounter('aba', '10');
exit;
You can fix part of the issue by updating $stringCounter inside the loop.
function printCounter($s, $n)
{
$stringCaller = '';
while (1) {
$stringCaller .= $s;
$stringCounter = strlen($stringCaller); // check strlen after each addition of $s
if ($stringCounter == $n) {
return $stringCaller;
}
}
}
However, even after you fix that issue, there will still be cases where your loop will never exit (such as the example in your question) because $stringCounter can only equal $n if $n is a multiple of strlen($s).
For the example printCounter('aba', '10');
Iteration $stringCounter ($stringCounter == $n)
1 3 false
2 6 false
3 9 false
4 12 false
Obviously $stringCounter will only get farther away from $n from that point.
So to ensure that the function will exit, check for inequality instead with:
if ($stringCounter >= $n) {
If you need the function to return exactly $n characters, the function will need to be a little more complex and take a substring of $s to make up the remaining characters when $stringCounter + strlen($s) will be greater than $n, or return an $n character substring of your result like this:
function printCounter($s, $n)
{
$result = '';
while (1) {
$result .= $s;
if (strlen($result) >= $n) {
return substr($result, 0, $n);
}
}
}
I'm are trying to teach myself to be better at programming. Part of this I have been taking puzzle that I find in newspapers and magazines and trying to find programming solutions
Today I seen a puzzle regarding numbers that are the reversed when multiplied by a number from 2-9. The example given was 1089 * 9 = 9801.
I have started to write a program in php to find the numbers this applies to and adds them to an array.
First I created a loop to cycle through the possible numbers. I then reversed each of the numbers and created a function to compare the numbered and the reversed number. The function then returns numbers that meet the criteria and adds them to an array.
This is what I have so far...
<?php
function mul(){ // multiply number from loop
for($i=2;$i<=9;$i++){
$new = $num * $i;
if($new == $re){
return $new;
}
else{
return;
}
}
}
$arr = array();
for ($num = 1000; $num <10000; $num++) { //loop through possible numbers
$re = strrev($num); // get reverse of number
func($re,$num); //multiply number and return correct numbers
$arr.push($new); //add to array??
}
?>
I'm still very new to php and I find understanding programming, any pointers on a more logical way of doing this puzzle would be greatly appreciated.
Here's my solution with a nested loop. Quick and dirty.
$result = array();
for ($i = 1000; $i < 5000; $i++) {
for ($m = 2; $m < 10; $m++) {
if ($i*$m == (int)strrev($i)) {
$result[] = array($i, $m);
}
}
}
var_dump($result);
I'd like to expand on this line:
if ($i*$m == (int) strrev($i)) {
One side is $i*$m, easy, the multipication.
On the other, we have (int)strrev($i), which means "Take $i, cast it to a string, and reverse that. Then cast it back into an int.
If that evaluates to true, an array containing $i and m is inserted into the $result array.
I was also looking for logical questions to solve to preparing for my interview. Thanks for sharing this question.I have solved this question but using Java.I have used very basic concept.I hope you can understand and convert it to php.
public static boolean processNumber(int number)
{
for(int i=2;i<=9;i++)
{
int reverseNumber=number*i;
boolean status=checkReverse(reverseNumber,number);
if(status)
{
return true;
}
}
return false;
}
public static boolean checkReverse(int reverseNumber,int numberOriginal)
{
int number=reverseNumber;
int reverse=0,digit;
do
{
digit=number%10;
number=number/10;
reverse=reverse*10+digit;
}while(number>0);
if(reverse==numberOriginal)
{
return true;
}
else
{
return false;
}
}
//This is my little effort towards programming check if it satisfy your requirements
$n = 1089;
$temp = $n;
$sum =0;
//reversing given number
while($n>1){
$rem = $n%10;
$sum = $sum*10 + $rem;
$n = $n/10;
}
//checking for digit that satisfy criteria
for($i=0; $i<=9; $i++){
if($i*$temp == $sum){
echo "$temp * $i = $sum";
}
}