c++ - error with define macro definition

Question

when i am using #define function,I observe something bizarre. In the below code if I gave i value as '10' from input i got the output as 132. However if I declare i=10 by commenting 10,12 and 13 lines then my output is 144. can anyone explain me how this is happening? thanks in advance

#include <iostream>
using namespace std;

#define Double(X) X*X 

int main()
{

 //int i=10;
 int i;

cout<<"Enter the i values:" <<endl;
cin>>i;

cout<<"Values is:"<<Double(++i)<<endl;

 return 0;
}

Answer 1

Double(++i) will expand to ++i * ++i. In this expression, i is modified twice without an intervening sequence point, which is undefined behavior.

Read: So, what's wrong with using macros?