Vector of pointers

[DEUX92yv]

I have a class, User, with a member string name;. In main(), I declare vector<User*> userList; and add a few pointers to User objects with

userList.push_back(new User);
userList[userList.size() - 1]->name = "a name";

Later, I want to print out each User's name, so I tried cout << userList[i]->name;, and nothing prints. I know (or at least I think) that the dot operator is not appropriate here. What is the correct way to access these members?

[vlad from moscow]

This statement

userList[userList.size()]->name = "a name";

is invalid because valid indexes are in the range [0, userList.size() - 1]

You could change this stattement to

userList.back()->name = "a name";

[DEUX92yv]

Sorry! I forgot about that. I got a seg fault error and in my actual file I'd already fixed it using .back(), but forgot to put that in this forum. I still don't get anything when I try to print though.

[vlad from moscow]

I do not see any problem to find the error. Simply include everywhere in the code test output of name. For example

userList.push_back( new User );
userList.back()>name = "a name";
std::cout << userList.back()->name << std::endl;

I think that the reason is somewhere either in the definition of the copy assignment operator of class User or in some operations with the list.

[DEUX92yv]

I've discovered that the problem is when I get the name as input. I use getline(cin, tempdata), where tempdata is a name followed by an age. The reason I have to use getline is that if tempdata is "done", I break out of the function, so I cannot use cin >> tempname >> tempage.

After that, I use a for loop to find out how many characters are in tempdata before the space, and copy the name into tempname. I know this is where my problem is now, but can't figure out what it is.

for (int i = 0; i < tempdata.length(); i++) {
	if (tempdata[i] == ' ') {		// Check name's length
		namelength = i;
		break;
	}
	else {
		tempname[i] = tempdata[i];		// Copy name
	}
}
cout << tempname;

The last cout statement does nothing.

[DEUX92yv]

I found a working solution to taking in input and splitting it into strings.

#include <sstream>
#include <iostream>
#include <vector>

int main() {
    std::vector<std::string> strings;
    std::istringstream f("denmark;sweden;india;us");
    std::string s;    
    while (std::getline(f, s, ';')) {
        std::cout << s << std::endl;
        strings.push_back(s);
    }
}