Calling member functions of objects vector

Question

So I have a vector declared like so:

vector <Game *> games;

and I have a function in the Game class like so:

public:

    // Rest of .h

    void hello(){
        cout << "hello" << endl;
    }

and I'm trying to iterate over my games vector using an iterator, and call the hello() function each time:

vector <Game *>::const_iterator it_games = games.begin();

for (it_games = games.begin(); it_games != games.end(); it_games++) {
    *it_games->hello();
}

but I keep getting this error when I try to compile:

main.cpp: In function ‘void summary(std::vector<Game*, std::allocator<Game*> >, std::string, std::string, std::string, std::string)’:
main.cpp:56: error: request for member ‘hello’ in ‘* it_games. __gnu_cxx::__normal_iterator<_Iterator, _Container>::operator-> [with _Iterator = Game* const*, _Container = std::vector<Game*, std::allocator<Game*> >]()’, which is of non-class type ‘Game* const’

Any idea what's going on/how I can get my desired functionality?

http://en.cppreference.com/w/cpp/language/operator_precedence : Of particular interest is the relative precedence of operators `*` and `->` — Benjamin Lindley, Sep 16 '13 at 00:20
Plus I should mention that my objects/vectors are being instantiated correctly. The problem comes when I try to access a member function/variable in he iterator loop. — Connor Black, Sep 16 '13 at 00:20
@BenjaminLindley, so you're saying I want something like `(*it_games)->hello()`? — Connor Black, Sep 16 '13 at 00:22
@BenjaminLindley, that worked. If you want to write up an answer I'll check it — Connor Black, Sep 16 '13 at 00:23
@chris, take a look at this: http://stackoverflow.com/questions/5270540/calling-derived-class-functions-from-within-a-vector-c — Connor Black, Sep 16 '13 at 00:32
@ConnorBlack, If you have polymorphism and dynamically allocate these, I recommend a `std::vector>`. — chris, Sep 16 '13 at 00:36

score 2 · Accepted Answer · answered Sep 16 '13 at 00:25

2

operator* has lower precedence than operator->. So this:

*it_games->hello();

should be this:

(*it_games)->hello();

answered Sep 16 '13 at 00:25

Benjamin Lindley

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or this: `it_games->hello();` – David G Sep 16 '13 at 00:26
@Connor Black: Correct, because it_games is an iterator over pointers, not a pointer itself – smocking Sep 16 '13 at 00:28
@ConnorBlack Right. I was mistaken, sorry! :) – David G Sep 16 '13 at 00:32

score 2 · Answer 2 · edited Sep 16 '13 at 00:27

2

-> has precedence, so the it_games pointer is not dereferenced before hello().

Change

*it_games->hello();

to

(*it_games)->hello();

edited Sep 16 '13 at 00:27

David G

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41
167
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answered Sep 16 '13 at 00:27

smocking

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Calling member functions of objects vector

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