php二分查找法

function er(arr,var){
low=0;globalcount;
count=0;height=count(arr)−1;while(low<=height){mid=intval((low+height)/2);
if(var>arr[mid])$low=$mid+1;if(var<arr[mid]){
height=mid-1;
}
if(var==arr[mid])return$mid;count++;
}
return false;

}
arr=range(1,5120000);echoer(arr,3342);
echo $count;