What is const_iterator

A const_iterator is not a const iterator. That is,

const vector<int>::iterator it;

and

vector<int>::const_iterator it;

are different. The first type (const iterator) does not allow any kind of modification of the iterator as well as the contents. That is, both

++it;

and

*it = 40 are illegal.

The second type(const_iterator) allows modification of the iterator, but prevents the contents from getting modified.

So,

++it is legal whereas *it = 40 is illegal.

#include<vector>

using namespace std;

int main()

{  

   vector<int> myVector;

   myVector.push_back(10);

   myVector.push_back(20);

   vector<int>::const_iterator it = myVector.begin();

   ++it;       // Legal 

   *it = 40;   // Illegal

   return 0;

}

How To Watch Pointer As An Array

At times, I had been annoyed that the watch window was not showing the whole contents of a pointer array until I found the trick.

Put in the watch window

Starting Address, No of elements to be shown

Please note that in the screen shot attached, the pointer has not been deleted. This may cause memory leaks. I’m sorry that I saw it only now.

How To Make gcc Warn You About Unused Variables

Use the option -Wunused with gcc.

gcc MyFile.cpp -Wunused