<?php
$max = 10;
$var2 = 0;
for($i = 0; $i <= $max; $i++){
$var3 = $var2; // Neste momento o $var2 ainda não pegou a linha atual
// consequentemente, terá sempre o valor da linha anterior
// ou zero, na primeira iteração (já que definimos zero fora do loop)
$var1 = $i * 100;
$var2 = $var1 * 50;
// Agora já temos $var1, $var2 e $var3 definidos, sendo que 1 e 2 são
// da linha corrente, e o 3 da anterior
echo '$var1:' . $var1 . ' - $var2:' . $var2 . ' - $var3:' . $var3 .PHP_EOL;
}
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