What is the difference between const_iterator and non-const iterator in the C++ STL?

Question

What is the difference between a const_iterator and an iterator and where would you use one over the other?

Answer 1

ok Let me explain it with very simple example first without using constant iterator consider we have collection of random integers collection "randomData"

    for(vector::iterator i = randomData.begin() ; i != randomData.end() ; ++i)*i = 0;
for(vector::const_iterator i = randomData.begin() ; i!= randomData.end() ; ++i)cout << *i;

As can be seen for writing/editing data inside collection normal iterator is used but for reading purpose constant iterator has been used . If you try using constant iterator in first for loop you will get error . As a thumb rule use constant iterator to read data inside collection .