<?php
header('Content-Type: text/html; charset=utf-8');
error_reporting(-1);

define('MONTHLYPAYMENT',5000);

function calculationOfCredit($creditBalance,$percent,$servicePayment,$openBalance)
{
$paymentTotal = null;
$month = 1;
while ($creditBalance > 0) {
 
    $creditBalance = ( $creditBalance * $percent ) + $servicePayment - MONTHLYPAYMENT;
    $paymentTotal = ($paymentTotal + MONTHLYPAYMENT);
 
    if ($creditBalance < 0) {
        $paymentTotal = ($paymentTotal + $creditBalance) + $openBalance;
        $creditBalance = 0;
        break;
    }
     	$month ++;
 	}
 	return $paymentTotal;
}
$HomoCredit = calculationOfCredit(39999,1.04,500,0);
echo "В HomoCredit анон всего заплатит {$HomoCredit}\n";
$Softbank = calculationOfCredit(39999,1.03,1000,0);
echo "В Softbank анон всего заплатит {$Softbank}\n";
$Strawberrybank = calculationOfCredit(39999,1.02,0,7777);
echo "В Strawberrybank анон всего заплатит {$Strawberrybank}\n";