A good PHP face Test (with answer)

A good PHP interview questions, with the answer, there are ready to change the work of the students can refer to.
First, the basic problem
1. Write out the output of the following program
<?php
$STR 1 = null;
$str 2 = false;
echo $str 1== $str 2? ' Equal ': ' Not equal ';
$str 3 = ";
$str 4 = 0;
Echo $str 3== $str 4? ' Equal ': ' Not equal ';
$str 5 = 0;
$str 6 = ' 0 ';
echo $str 5=== $str 6? ' Equal ': ' Not equal ';
?>
2. Write out the output of the following program
<?php
$a 1 = null;
$a 2 = false;
$a 3 = 0;
$a 4 = ";
$a 5 = ' 0 ';
$a 6 = ' null ';
$a 7 = array ();
$a 8 = Array (array ());
echo empty ($a 1)? ' True ': ' false ';
echo Empty ($a 2)? ' True ': ' false ';
echo Empty ($a 3)? ' True ': ' false ';
echo Empty ($a 4)? ' True ': ' false ';
echo Empty ($a 5)? ' True ': ' false ';
echo Empty ($a 6)? ' True ': ' false ';
echo Empty ($a 7)? ' True ': ' false ';
echo empty ($a 8)? ' True ': ' false ';
?>
3. Write out the output of the following program
<?php
$test = ' aaaaaa ';
$ABC = & $test;
Unset ($test);
Echo $abc;
?>
4. Write out the output of the following program
<?php
$count = 5;
function get_count () {
static $count = 0;
return $count + +;
}
Echo $count;
+ + $count;
Echo get_count ();
Echo get_count ();
?>
5. Write out the output of the following program
<?php
$GLOBALS [' var1 '] = 5;
$var 2 = 1;
function Get_value () {
Global $var 2;
$var 1 = 0;
return $var 2++;
}
Get_value ();
echo $var 1;
echo $var 2;
?>
6. Write out the output of the following program
<?php
function Get_arr ($arr) {
unset ($arr [0]);
}
$arr 1 = Array (1, 2);
$arr 2 = Array (1, 2);
Get_arr (& $arr 1);
Get_arr ($arr 2);
echo Count ($arr 1);
echo Count ($arr 2);
?>
7. Get the extension of a file using more than five different ways
Requirements: dir/upload.image.jpg, find. jpg or JPG,
Must be handled using PHP's own processing function, which cannot be significantly duplicated and can be encapsulated into functions such as GET_EXT1 ($file _name), get_ext2 ($file _name)

Second, the algorithm problem
1. Using PHP to describe the bubble sort and quick sort algorithm, an object can be an array
2. Using PHP to describe order lookup and binary lookup (also called binary lookup) algorithm, sequential lookup must consider efficiency, an object can be an ordered array
3. Write a two-dimensional array sorting algorithm function, which can be universal, call PHP built-in functions

Answer
(The following answer is not necessarily the best, just a simple reference)
First, the basic problem
1. Equality and equality are not equal
2. True True True True false
3. AAAAAA Reference: http://my.oschina.net/banbo/blog/303306

4.5 0 1
5.5 2
6.1 2
7. Get the extension of a file using more than five different ways
function Get_ext1 ($file _name) {
Return STRRCHR ($file _name, '. ');
}
function get_ext2 ($file _name) {
Return substr ($file _name, Strrpos ($file _name, '. '));
}
function Get_ext3 ($file _name) {
Return Array_pop (Explode ('. ', $file _name));
}
function Get_ext4 ($file _name) {
$p = PathInfo ($file _name);
return $p [' extension '];
}
function Get_ext5 ($file _name) {
Return Strrev (substr (Strrev ($file _name), 0, Strpos (strrev ($file _name), '. '));
}

Second, the algorithm problem
1. Using PHP to describe the bubble sort and quick sort algorithm, an object can be an array
Bubble sort (Array sort)
function Bubble_sort ($array) {
$count = count ($array);
if ($count <= 0) return false;
for ($i =0; $i < $count; $i + +) {
for ($j = $count-1; $j > $i; $j-) {
if ($array [$j] < $array [$j-1]) {
$tmp = $array [$j];
$array [$j] = $array [$j-1];
$array [$j-1] = $tmp;
}
}
}
return $array;
}
Quick sort (Array sort)
function Quick_sort ($array) {
if (count ($array) <= 1) return $array;
$key = $array [0];
$left _arr = Array ();
$right _arr = Array ();
for ($i =1; $i <count ($array); $i + +) {
if ($array [$i] <= $key)
$left _arr[] = $array [$i];
Else
$right _arr[] = $array [$i];
}
$left _arr = Quick_sort ($left _arr);
$right _arr = Quick_sort ($right _arr);
Return Array_merge ($left _arr, Array ($key), $right _arr);
}
2. Using PHP to describe order lookup and binary lookup (also called binary lookup) algorithm, sequential lookup must consider efficiency, an object can be an ordered array
Binary lookup (Find an element in an array)
function Bin_sch ($array, $low, $high, $k) {
if ($low <= $high) {
$mid = Intval (($low + $high)/2);
if ($array [$mid] = = $k) {
return $mid;
}elseif ($k < $array [$mid]) {
Return Bin_sch ($array, $low, $mid-1, $k);
}else{
Return Bin_sch ($array, $mid +1, $high, $k);
}
}
return-1;
}
Order lookup (Find an element in an array)
function Seq_sch ($array, $n, $k) {
$array [$n] = $k;
for ($i =0; $i < $n; $i + +) {
if ($array [$i]== $k) {
Break
}
}
if ($i < $n) {
return $i;
}else{
return-1;
}
}
3. Write a two-dimensional array sorting algorithm function, which can be universal, call PHP built-in functions
Two-dimensional array sorting, $arr is the data, $keys is the sort of health value, $order is the collation, 1 is ascending, 0 is descending
function Array_sort ($arr, $keys, $order =0) {
if (!is_array ($arr)) {
return false;
}
$keysvalue = Array ();
foreach ($arr as $key = = $val) {
$keysvalue [$key] = $val [$keys];
}
if ($order = = 0) {
Asort ($keysvalue);
}else {
Arsort ($keysvalue);
}
Reset ($keysvalue);
foreach ($keysvalue as $key = = $vals) {
$keysort [$key] = $key;
}
$new _array = Array ();
foreach ($keysort as $key = = $val) {
$new _array[$key] = $arr [$val];
}
return $new _array;
}