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较长数字 字符串 的比较有关问题

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2016-06-13 11:42:58851browse

较长数字 字符串 的比较问题

本帖最后由 anyilaoliu 于 2013-12-13 15:04:43 编辑 如题 
遇到这样的问题

<br />$a = "222111565652521142";<br />		$b = "222111565652521139";<br />		$c = 222111565652521142;<br />		$d = 222111565652521139;<br /><br />		var_dump($a);<br />		echo "<br/>";<br />		var_dump($b);<br />		echo "<br/>";<br />		var_dump($c);<br />		echo "<br/>";<br />		var_dump($d);<br />		echo "<br/>";<br /><br />		if ($a == $b) {<br />			echo 3;<br />		}else{<br />			echo 31;<br />		}<br />		echo "<br/>";<br /><br />		if ($c == $d) {<br />			echo 4;<br />		}else{<br />			echo 41;<br />		}<br />		echo "<br/>";<br />


结果是


<br /><br /><br />string '222111565652521142' (length=18)<br /><br /><br />string '222111565652521139' (length=18)<br /><br /><br />float 2.2211156565252E+17<br /><br /><br />float 2.2211156565252E+17<br /><br /><br /><br />31<br />4<br />


问题来了,第二种情况 如何进行两者的比较

问题二: 从数据库中读出来的这两组数字,var_dump后显示是string(18)  但是比较结果和上边的例子恰好相反,两个string的 比较相等 也通过了.

求解
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