PHP cannot connect to MYSQL. how can this problem be solved?

PHP cannot connect to MYSQL $ con = mysql_connect (& quot; localhost & quot;, & quot; root & quot;, & quot; 123456 & quot;); if (! $ Con) {die ('couldnotconnect: '. m PHP cannot connect to MYSQL
$ Con = mysql_connect ("localhost", "root", "123456 ");
If (! $ Con ){
Die ('could not connect: '. mysql_error ());
} Else {
Echo 'suc ';
}
I wrote such a program.
The following error is prompted:
PHP has encountered an Access Violation at 0155AC5A
A friend who is in trouble knows how to give a clear path.

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Php unauthorized access:
Http://www.jb51.net/article/10072.htm