PHPFlowControl

//1. Exchange value

<!--Write an if statement that examines two integer variables and exchanges their values if the first one is greater than
the second one.-->

<h1 style="font-size: 1.2em">Change Variable Value</h1>
<form action="1_ExchangeValue.php" method="post">
    <input type="text" name="a" value="a"><br>
    <input type="text" name="b" value="b">
    <input type="submit" value="Go">
</form>
<?php
if(isset($_POST['a'],$_POST['b'])){
    $a = $_POST['a'];
    $b = $_POST['b'];
    echo "a= ".$a.",b= ".$b.'<br>';
    if($a>$b){
        $c = $a;
        $a = $b;
        $b = $c;
        echo 'Result: ';
        echo "a= ".$a.",b= ".$b;
    }  else {
        echo 'Change value only when a>b!';
    }
}
?>

//2. Show sign
//3. Sort numbers

<!--Sort 3 real values in descending order using nested if statements.-->

<?php
$numbers = array("a" => 5, "b" => 4, "c" => 3, "d" => 2);
asort($numbers);
foreach ($numbers as $key => $val) {
    echo "$key = $val.<br>";
}
?>

//4. Point in a Circle

<!--Write an expression that checks if given point (x, y) is inside a circle K({0, 0}, 2). Examples:

x     y      inside
0     1       true
-2    0       true
-1    2      false
1.5  -1       true
-1.5 -1.5     false
100  -30      false
0      0      true
0.2  -0.8     true
0.9  -1.93   false
1     1.655   true-->

<h1 style="font-size: 1.2em">Point in a Circle</h1>
<form action="4_PointInCircle.php" method="post">
    <input type="text" name="x" value="x"><br>
    <input type="text" name="y" value="y">
    <input type="submit" value="Go">
</form>
<?php
  if(isset($_POST['x'],$_POST['y'])){
    $x = $_POST;
    $y = $_POST;
    $circle = (($x*$x)+($y*$y))<=2*2;
        echo $circle ? 'True':'False';

  }
?>

//5. Matrix of Numbers

<!--Write a program that reads from the console a positive integer number n (1 ≤ n ≤ 20) and prints a matrix like in the
examples below. Use two nested loops. Examples:
n matrix n matrix n matrix

1 2
2
2 3 3
1 2 3
2 3 4
3 4 5
1 2 3 4
2 3 4 5
4
3 4 5 6
4 5 6 7-->

<h1 style="font-size: 1.2em">Matrix Of Numbers</h1>
<form action="5_MatrixOfNumbers.php" method="post">
    <input type="text" name="a" value="x"><br>
    <input type="submit" value="Go">
</form>
<?php
if(isset($_POST['a'])){
    $n = $_POST['a'];
    for ($row = 1; $row <= $n; $row++) {
        for ($i = $row; $i < $n+$row; $i++) {
            //echo ' ','<br>';
            echo $i;
            echo ' ';
        }
        echo ' '.'<br>';
    }
}
?>

//6. Odd and Even Product
//7. TOTO

for ($i = 1; $i <=40; $i++) {
    for ($j = $i+1; $j <=41; $j++) {
        for ($y = $j+1; $y <=42; $y++) {
            echo $i.' '.$j.' '.$y;
        }
    }
}
?>

//8. Print Prime Numbers

<?php
function prime($n){
for($i=1;$i<=$n;$i++){
    $counter = 0;
    for($j=1;$j<=$i;$j++){
        if($i % $j==0){
            $counter++;
                }
        }
        if($counter==2){
            print $i." is Prime <br>";
        }
    }
}
prime(100);

//9. Extract words

<!--Write a function that takes as argument an array, and extract all the words from that array without repeating the
same ones.

Array result
Nakov,
Svetlin,
Nakov, Pesho,
Mario,
Dimityr,
Georgi, Mario


Nakov, Svetlin,
Pesho, Mario,
Dimityr,Georgi-->


<?php
$input = array("Nakov", "Svetlin","Nakov", "Pesho", "Mario","Dimityr","Georgi","Mario");
print_r(array_unique($input));
?>