Determining Binary Search Running Time & Understanding

[zak100]

Homework Statement

Hi,

I have a problem understanding the following equation related to binary search:

Homework Equations

int midIndex = (endIndex - startIndex / 2) + startIndex;

The Attempt at a Solution

If: endIndex = 10
startIndex = 0

then midIndex = (10 - 0/2) + 0;
midIndex = (10-0) +0;
midIndex = 10;
I don't think, this is right. midIndex should be 5 as name implies.

Some body please guide, what's my error.

Zulfi.

 

[phinds]

int midIndex = (endIndex - startIndex / 2) + startIndex;

You must have copied this incorrectly. It should be (endindex - startindex)/2 + startindex

 

[BvU]

the following equation

Where did you find that equation ?
Is it as simple as a typo and what you want is int midIndex = (endIndex - startIndex ) / 2 + startIndex;

 

[zak100]

Hi,
Thanks for your prompt reply. I got it from here:

http://www.mcs.csueastbay.edu/~bhecker/Previous Terms/CS-3240-Sum14/Examples/BigOExamples.java

Thanks for removing my confusion.

Zulfi.