Email validation, Am I doing the right thing? - php

Question

I am writing some PHP code where I end it with a email validation checking. Can someone review it and confirm if it's a good solution?
<?php
function isTrue($var) {
return (isset($var)) ? TRUE : FALSE;
}
function len($str) {
$i;
for($i=0; isTrue($str[$i]); $i++) {
/* count me */
}
return $i;
}
function parsMe($str) {
$at; $dot; $isvalid=0; $isnotvalid=0;
for ( $at=0; isTrue($str[$at]); $at++) {
if ( $str[$at] == "#" ) {
for ( $dot=$at+1; isTrue($str[$dot]); $dot++ ) {
if ( $str[$dot] == "." ) $isvalid += 1;
if ( $str[$dot] =="#" || $str[len($str)-1] == "#" || $str[len($str)-1] == "." ) {
die("Error email entered");
}
}
}
if ( $str[$at] != "#" ) {
$isnotvalid+=1;
}
}
/* exit cond */
if ( $isnotvalid == len($str) ) die("Error mail usage");
else if ( $isvalid == 0 ) die("Error mail");
else echo "Mail is OK ";
}
$eml = "dotdot#com.";
parsMe($eml);
?>
parsMe() should produce error.

Answer 1

There are built in functions for checking validity of emails:
<?php
$email ='dotdot#com';
if(!filter_var($email, FILTER_VALIDATE_EMAIL)){
echo "E-mail is not valid";
}else{
echo "E-mail is valid";
}
?>