PHP/Data Structure/Stack
Содержание
array_pop: Pop the element off the end of array
<source lang="html4strict">
<?php
$states = array("Ohio","New York","California","Texas");
$state = array_pop($states); // $state = "Texas"
print_r($states);
?>
</source>
array_push: Push one or more elements onto the end of array
<source lang="html4strict">
<?php $states = array("Ohio","New York"); array_push($states,"California","Texas"); // $states = array("Ohio","New York","California","Texas"); print_r($states); ?>
</source>
A stack with type restricted to int
<source lang="html4strict">
<? class IntStack {
var $the_stack;
var $count = 0;
function push ($intvar) {
if (is_integer($intvar)) {
$this->the_stack[$this->count] = $intvar;
$this->count++;
print("Push of $intvar succeeded.
");
} else {
print("Hey, IntStack is for ints only!
");
}
}
function pop () {
if ($this->count > 0) {
$this->count--; // decrement count
$top = $this->the_stack[$this->count];
return($top);
} else {
print("Hey, the stack is empty!
");
}
}
}
$my_stack = new IntStack;
$my_stack->push(1);
$my_stack->push(49);
$my_stack->push("A");
$pop_result = $my_stack->pop();
print("Top of the stack was $pop_result
");
$pop_result = $my_stack->pop();
print("Top of the stack was $pop_result
");
$pop_result = $my_stack->pop();
print("Top of the stack was $pop_result
");
?>
</source>
Stack in Use
<source lang="html4strict">
<html> <head> <title>Stack</title> </head> <body> <?php
$stack = array();
$book_one = "One";
$book_two = "Two";
$book_three = "Three";
array_push($stack, $book_one);
array_push($stack, $book_three);
array_push($stack, $book_two);
$n = count ($stack);
while ($book = array_pop ($stack)) {
print ("Item $n: $book
\n");
$n--;
}
?> </body> </html>
</source>
