$end

 = 

$middle

 - 1 ; 

} 

elseif

 (

$arrData

[

$middle

] < 

$val

) { 

$start

 = 

$middle

 + 1; 

} 
} 

return

 -1; 

} 
 

// 测试一下二分法查找 

$arrData

 = 

array

(1,2,3,4,5,7,8,9,11,23,56,100,104,578,1000); 

echo

 binary_search(

$arrData

,578),"<br/>"; 

echo

 binary_search(

$arrData

,66),"<br/>";