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<title>PHP Function</title>
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function sum($value1 = 0, $value2, $value3 = 0)
{
return $value1 + $value2 + $value3;
}
echo sum(1, 2, 3)."<br>"; // 6
echo sum(1, 2)."<br>"; // 3
//echo sum(1); // 오류가 발생함.
//echo sum(); // 오류가 발생함.
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