Thread: reverse member function

Originally Posted by Aisthesis

Gaddis (p. 451) has a reverse function for vectors that MS doesn't seem to recognize.

Just experimenting around with his various vector member functions, I have the vector NumVect1 with 5 integer members (and I have the #include <vector> header), but when I put in the line of code:

The reverse function that tabstop mentioned is actually a non-member function template. The author that you mentioned probably did not demonstrate the use of a reverse member function for std::vector since there is no such member function.

If the author did demonstrate the use of such a member function, then it is time to put that book aside and get one that actually teaches you standard C++.

Originally Posted by Aisthesis

He just lists it in his "summary of vector member functions" on pp. 450-451 (6th ed.) but doesn't actually demonstrate it except to give as example:

vect.reverse();

Will that work if I try the <algorithm> header?

Should do, yes.

--
Mats

Originally Posted by Aisthesis

He just lists it in his "summary of vector member functions" on pp. 450-451 (6th ed.) but doesn't actually demonstrate it except to give as example:

vect.reverse();

Just a moment. It occurred to me that perhaps you misread reserve as reverse. The former is the name of a member function of std::vector.

Originally Posted by Aisthesis

Will that work if I try the <algorithm> header?

No, unless your standard library implementation provided std::vector with a reverse member function as a library extension. The correct code would be:

Code:

std::reverse(vect.begin(), vect.end());

EDIT:
On second thought, the example would not be a correct call of reserve anyway, so it does seem like the author has given misinformation.

Originally Posted by Aisthesis

Anyhow, this code won't compile (but will if you exclude the line with the reverse pseudo-function):

Try:

Code:

// testing "reverse" syntax

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main()
{
	int Place;
	vector<int> NumVect;

	for (Place = 0; Place < 10; Place++)
		NumVect.push_back(Place + 1);

	cout << "First position in our vector is now " << NumVect[0] << endl
		<< "Tenth position in our vector is now " << NumVect[9] << endl;

	reverse(NumVect.begin(), NumVect.end());

	cout << "First position in our vector is now " << NumVect[0] << endl
		<< "Tenth position in our vector is now " << NumVect[9] << endl;

	return 0;
}

Now, what is the full title of this book? Gaddis has at least two books with titles that start with "Starting Out with C++". You are using the 6th edition of this book? I noticed that in another thread you mentioned 5th edition.

Unfortunately, that book is not in my local library, so getting a copy of it to review it at no cost to myself will not be easy. The error may be a one off thing (but repeated twice?), but it could also be symptomatic of other factual problems.