**Answer**

Note: array should be sorted or Binary search won't work !

int binarySearch(int arr[],int size, int item)

{

int left, right, middle;

left = 0;

right = size-1;

while(left <= right)

{

middle = ((left + right)/2);

if(item == arr[middle])

{

return(middle);

}

if(item > arr[middle])

{

left = middle+1;

}

else

{

right = middle-1;

}

}

return(-1);

}