Constant vector iterators

[Russ Ford]

How does one define an iterator for a constant vector?

ie:
void printvector (vector<int>& arr)
{
vector<int>::iterator i;
for (i=arr.begin(); i<arr.end(); ++i)
cout << *i << endl;
}

works fine, but if I change the prototype to
void printvector (const vector<int>& arr)
I get a compile error on the for line about trying to convert a const int*
const to an int*.

How do I specify that it's the vector that's constant and not the iterator
itself?

Much appreciated.

Russ

 

[Pete C.]

How does one define an iterator for a constant vector?

ie:
void printvector (vector<int>& arr)
{
vector<int>::iterator i;
for (i=arr.begin(); i<arr.end(); ++i)
cout << *i << endl;
}

works fine, but if I change the prototype to
void printvector (const vector<int>& arr)
I get a compile error on the for line about trying to convert a const
int* const to an int*.

How do I specify that it's the vector that's constant and not the
iterator itself?

Much appreciated.

Russ

vector<T>::const::iterator

- Pete

 

[Pete C.]

How does one define an iterator for a constant vector?

ie:
void printvector (vector<int>& arr)
{
vector<int>::iterator i;
for (i=arr.begin(); i<arr.end(); ++i)
cout << *i << endl;
}

works fine, but if I change the prototype to
void printvector (const vector<int>& arr)
I get a compile error on the for line about trying to convert a const
int* const to an int*.

How do I specify that it's the vector that's constant and not the
iterator itself?

Much appreciated.

Russ

std::vector<T>::const_iterator

- Pete

 

[Pete C.]

vector<T>::const::iterator

- Pete

Sorry, ignore, I hit send before I finished

 

[Rolf Magnus]

How does one define an iterator for a constant vector?

Use a const_iterator.

ie:
void printvector (vector<int>& arr)
{
vector<int>::iterator i;
for (i=arr.begin(); i<arr.end(); ++i)
cout << *i << endl;
}

works fine, but if I change the prototype to
void printvector (const vector<int>& arr)
I get a compile error on the for line about trying to convert a const
int* const to an int*.

void printvector (const vector<int>& arr)
{
vector<int>::const_iterator i;
for (i=arr.begin(); i<arr.end(); ++i)
cout << *i << endl;
}

How do I specify that it's the vector that's constant and not the
iterator itself?

When defining the iterator, you don't describe whether the vector you
use it with is const or not. You describe whether you want to use the
iterator for writing (iterator) or for reading (const_iterator).

 

[Russ Ford]

Sorry, ignore, I hit send before I finished

Thanks very much guys.

 

[Pete Becker]

How does one define an iterator for a constant vector?

ie:
void printvector (vector<int>& arr)
{
vector<int>::iterator i;
for (i=arr.begin(); i<arr.end(); ++i)
cout << *i << endl;
}

works fine, but if I change the prototype to
void printvector (const vector<int>& arr)
I get a compile error on the for line about trying to convert a const int*
const to an int*.

How do I specify that it's the vector that's constant and not the iterator
itself?

It's easier to write code that doesn't care:

void printvector(const vector<int>& arr)
{
std::copy(arr.begin(), arr,end(), std:stream_iterator(std::cout));
}

 

[Sergiy Kanilo]

It's easier to write code that doesn't care:

void printvector(const vector<int>& arr)
{
std::copy(arr.begin(), arr,end(), std:stream_iterator(std::cout));

std::copy(arr.begin(), arr.end(),

}

Cheers,
Serge