Write to and read from a text file in Php

The function write_log below writes the contents of an array $contentstowrite to a text file log.txt (The array and filename can be modified as required). The content to write should be an array or else it displays an error.

// Writing to a text file
function write_log($filename,$towrite){
echo "Supplied content to write is not an array, a valid array is required to write";

/* Second parameter description for the above function fopen
w+ --> opens a file and creates new contents replacing old. If the file does not exist, attempts to create it.
a+ --> opens a file and appends to it. If the file does not exist, attempts to create it.
foreach($towrite as $key=>$val){

echo "Successfully written to log";
fclose($fw); // closes an open file pointer $fw

$contentstowrite = array('dell','apple','hp','vaio');

This function read_log below is used to read the contents of the file log.txt (can be modified as required) and display it.

// Reading from a text file
function read_log($filename){
$fd=fopen($filename,"r"); // opens a file for reading only
$out = "



// If the file cannot be read or doesn't exist,the function fopen returns FALSE
// FALSE from fopen will issue warning and result in infinite loop when calling the function feof
// So to avoid the infinite loop and filling of the error logs, we call feof only if $fd returns TRUE
while(!feof($fd)) {
$out .= "

$line = fgets($fd,4096); // Gets a line from the file
// The second optional parameter 4096 is the line length of a file to be read
// Reading ends after this length, we have to increase it if the file has larger lines to be read.
$out .= $line."

fclose($fd); // closes an open file pointer $fd

return $out;
echo read_log('log.txt');

The final output of the whole code is displayed below. I have set the fopen mode to append while writing to a file. Hence, everytime we run this code, the same contents are appended to the log over and over again.

Successfully written to log