Introduction to Algorithms exercise 2.3-52 Search Binary Searches

Earth people know "binary search", the method is very simple, but can you write a bug-free program within 10 minutes?

Easier, write it yourself and try it.

 Public classBinarySearch { Public Static intSearchint[] A,intTargetintAintb) {intMiddle = (a+b)/2; if(a>b)return-1; Else if(a[middle]==target)returnMiddle; Else if(a[middle]<target)returnSearch (a,target,middle+1, B); Else             returnSearch (a,target,a,middle-1); }     Public Static voidMain (string[] args) {//TODO auto-generated Method Stub        intA [] = {2,4,6,8,10}; System.out.println (Binarysearch.search (A,1, 0, a.length-1)  ); System.out.println (Binarysearch.search (A,2, 0, a.length-1)  ); System.out.println (Binarysearch.search (A,3, 0, a.length-1)  ); System.out.println (Binarysearch.search (A,4, 0, a.length-1)  ); System.out.println (Binarysearch.search (A,5, 0, a.length-1)  ); System.out.println (Binarysearch.search (A,6, 0, a.length-1)  ); System.out.println (Binarysearch.search (A,7, 0, A.length-1)  ); System.out.println (Binarysearch.search (A,8, 0, A.length-1)  ); System.out.println (Binarysearch.search (A,9, 0, A.length-1)  ); System.out.println (Binarysearch.search (A,Ten, 0, a.length-1) ); System.out.println (Binarysearch.search (A,One, 0, a.length-1) ); }}

The above code seems to have no problem, but there is still a very subtle bug, this bug occurred in:

int  middle = (a+b)/2;

This line. Think about it, if the a+b exceeds the maximum value of the int type???
So, fixing the bug should look like this:

 Public classBinarySearch { Public Static intSearchint[] A,intTargetintAintb) {intMiddle = a + (b-a)/2; if(a>b)return-1; Else if(a[middle]==target)returnMiddle; Else if(a[middle]<target)returnSearch (a,target,middle+1, B); Else             returnSearch (a,target,a,middle-1); }     Public Static voidMain (string[] args) {//TODO auto-generated Method Stub        intA [] = {2,4,6,8,10}; System.out.println (Binarysearch.search (A,1, 0, a.length-1)  ); System.out.println (Binarysearch.search (A,2, 0, a.length-1)  ); System.out.println (Binarysearch.search (A,3, 0, a.length-1)  ); System.out.println (Binarysearch.search (A,4, 0, a.length-1)  ); System.out.println (Binarysearch.search (A,5, 0, a.length-1)  ); System.out.println (Binarysearch.search (A,6, 0, a.length-1)  ); System.out.println (Binarysearch.search (A,7, 0, A.length-1)  ); System.out.println (Binarysearch.search (A,8, 0, A.length-1)  ); System.out.println (Binarysearch.search (A,9, 0, A.length-1)  ); System.out.println (Binarysearch.search (A,Ten, 0, a.length-1) ); System.out.println (Binarysearch.search (A,One, 0, a.length-1) ); }}

The end ...

Introduction to Algorithms exercise 2.3-52 Search Binary Searches