JGari.com

/* start yahoo settings */
$yinterest=5; // yahoo growth rate
$ypv = 115401; // yahoo unique visitors in February 2006 (http://www.washingtonpost.com/wp-dyn/content/custom/2006/03/31/CU2006033101136.html)
/* end yahoo settings */

$match_in_months = -1;
$months = 1;
$match = false;

$start_date=strtotime($report_date,time());
print_value("Stat Date","Yahoo","Google","Difference","Margin");
print_value("---------","-----","------","----------","------");

while(!$match){
$google_fv = fv($ginterest, $months, $gpv);
$yahoo_fv = fv($yinterest, $months, $ypv);
$yahoo_fv = number_format($yahoo_fv,0,"",""); // remove decimals
$google_fv = number_format($google_fv,0,"",""); // remove decimals

if(($google_fv >= $yahoo_fv)){
$match_in_months = $months;
$match = true;
}
$difference = ($yahoo_fv - $google_fv);
$margin = ((($yahoo_fv - $google_fv)/$google_fv)*100);
$margin = number_format($margin,2)."%";
$stat_date =strtotime("+$months months",$start_date);
$stat_date = date("M Y",$stat_date);
print_value($stat_date, number_format($yahoo_fv,0), number_format($google_fv,0),number_format($difference,0),$margin);
//print "$stat_date\t\t$yahoo_fv\t\t$google_fv\n";
$months++;
}

$yahoo_fv = number_format($yahoo_fv,0); // format value
$google_fv = number_format($google_fv,0); // format value

print "\nMatch in $match_in_months months\nWith Google $google_fv and Yahoo $yahoo_fv unique visitors\n\n";

/*
Author: Jorge Garifuna
Email: info@GariDigital.com
Website: http://www.GariDigital.com
Created: May 13, 2006
This function calculates the Future Value

@params
- $pv : accumulated quantity (eg: 9000 for 9,000)
- $period : number of months (eg: 120)
- $interest : interest or growth rate (eg: 5 for 5%)

returns
- the future value
*/
function fv($interest, $period, $pv){
$interest /= 100;
$interest /= 12;
$fv = ($pv * pow(1+$interest, $period)); // compute future value
return $fv;
}

/*
Author: Jorge Garifuna
Email: info@GariDigital.com
Website: http://www.GariDigital.com
Created: May 13, 2006
This function prints a formated version of the the output

@params
- $date_info : either the stat date header label or the actual date value
- $yahoo_info : either the yahoo header label or the actual unique visitors value
- $google_info : either the google header label or the actual unique visitors value
- $difference : the difference in quantity of unique visitors between Google and Yahoo
- $margin : the difference in percentage of unique visitors between Google and Yahoo
*/
function print_value($date_info, $yahoo_info, $google_info,$difference,$margin){
print "$date_info\t$yahoo_info\t\t$google_info\t\t$difference\t\t$margin\n";
}
?>