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Vector of Class-Object pointers: How to get value at pointer address? C++ and SDL_Rect
2019 Community Moderator ElectionHow can I profile C++ code running on Linux?c++ vector.push_back error: request for member 'push_back'…, which is of non-class type 'vector(char, allocator(char)) ()()'C++ Iterators, interfaces and pointersTrying to use std::vector<MyClass>How to store a vector of objects of an abstract class which are given by std::unique_ptr?Does std::vector<Object> reserve method need a copy constructor for Object class?Why should I use a pointer rather than the object itself?Passing vector pointer in c++Expression must have class type. - Vector of class objectsC++: Vector of Pointers to Objects from another Vector
I've got a vector of class-object pointers. I declare the vector in main..:
std::vector<Class1*> vector1;
vector1.push_back(&object1);
vector1.push_back(&object2);
The below error occurs. This is just the simplest variant of trying to access data contained within the class pointed to by the vector.
Ex:
Main.cpp:
std::cout << vector1[0]->rect->w << std::endl;
Class1.h
SDL_Rect rect100, 100, 50, 50;
The above results in a red underline of the word 'Vector1' with the error "Expression must have a valid pointer type".
EDIT:
Forgot to mention that I'm trying to get to a SDL_Rect contained within the Class-Objects pointed to by the vector... Not sure how/if that changes anything.
I'll provide more complete code when I'm off work.
The code I've provided works if I simply specify a variable of a normal type such an int (where 'age' below is an int):
std::cout << vector1[0]->age << std::endl;
But since I'm specifying an SDL_Rect in the example from Main.cpp I get the error I mentioned. Anyone know what the peculiarity is?
c++ c++11 c++14 sdl stdvector
asked Mar 7 at 15:30
ArianaxArianax
13
|
show 2 more comments
I've got a vector of class-object pointers. I declare the vector in main..:
std::vector<Class1*> vector1;
vector1.push_back(&object1);
vector1.push_back(&object2);
The below error occurs. This is just the simplest variant of trying to access data contained within the class pointed to by the vector.
Ex:
Main.cpp:
std::cout << vector1[0]->rect->w << std::endl;
Class1.h
SDL_Rect rect100, 100, 50, 50;
The above results in a red underline of the word 'Vector1' with the error "Expression must have a valid pointer type".
EDIT:
Forgot to mention that I'm trying to get to a SDL_Rect contained within the Class-Objects pointed to by the vector... Not sure how/if that changes anything.
I'll provide more complete code when I'm off work.
The code I've provided works if I simply specify a variable of a normal type such an int (where 'age' below is an int):
std::cout << vector1[0]->age << std::endl;
But since I'm specifying an SDL_Rect in the example from Main.cpp I get the error I mentioned. Anyone know what the peculiarity is?
c++ c++11 c++14 sdl stdvector
asked Mar 7 at 15:30
ArianaxArianax
13
vector1[i]yields a pointer like any other. Just use->like you would for a regularClass1*. Edit : Actually, I'm just assuming. Your function isn't actually legal c++ so it's not possible to say with certainty at this point.
– François Andrieux
Mar 7 at 15:30
3
exampleFunction(vector1, int offset 5)this is invalid C++ code, please edit and clarify
– Jabberwocky
Mar 7 at 15:31
instead of vector1[i].width += offset; do vector1[i]->width += offset;
– user2320641
Mar 7 at 15:33
1
Please read Minimal, Complete, and Verifiable example for guidelines on providing complete and helpful examples. Please only share real code that you've tried yourself.
– François Andrieux
Mar 7 at 15:34
1
@Arianax Then I don't know what the problem is. Please post a MCVE (see my previous comment for a link) and then we might be able to help you.
– François Andrieux
Mar 7 at 15:41
|
show 2 more comments
I've got a vector of class-object pointers. I declare the vector in main..:
std::vector<Class1*> vector1;
vector1.push_back(&object1);
vector1.push_back(&object2);
The below error occurs. This is just the simplest variant of trying to access data contained within the class pointed to by the vector.
Ex:
Main.cpp:
std::cout << vector1[0]->rect->w << std::endl;
Class1.h
SDL_Rect rect100, 100, 50, 50;
The above results in a red underline of the word 'Vector1' with the error "Expression must have a valid pointer type".
EDIT:
Forgot to mention that I'm trying to get to a SDL_Rect contained within the Class-Objects pointed to by the vector... Not sure how/if that changes anything.
I'll provide more complete code when I'm off work.
The code I've provided works if I simply specify a variable of a normal type such an int (where 'age' below is an int):
std::cout << vector1[0]->age << std::endl;
But since I'm specifying an SDL_Rect in the example from Main.cpp I get the error I mentioned. Anyone know what the peculiarity is?
c++ c++11 c++14 sdl stdvector
asked Mar 7 at 15:30
ArianaxArianax
13
I've got a vector of class-object pointers. I declare the vector in main..:
std::vector<Class1*> vector1;
vector1.push_back(&object1);
vector1.push_back(&object2);
The below error occurs. This is just the simplest variant of trying to access data contained within the class pointed to by the vector.
Ex:
Main.cpp:
std::cout << vector1[0]->rect->w << std::endl;
Class1.h
SDL_Rect rect100, 100, 50, 50;
The above results in a red underline of the word 'Vector1' with the error "Expression must have a valid pointer type".
EDIT:
Forgot to mention that I'm trying to get to a SDL_Rect contained within the Class-Objects pointed to by the vector... Not sure how/if that changes anything.
I'll provide more complete code when I'm off work.
The code I've provided works if I simply specify a variable of a normal type such an int (where 'age' below is an int):
std::cout << vector1[0]->age << std::endl;
But since I'm specifying an SDL_Rect in the example from Main.cpp I get the error I mentioned. Anyone know what the peculiarity is?
c++ c++11 c++14 sdl stdvector
c++ c++11 c++14 sdl stdvector
asked Mar 7 at 15:30
ArianaxArianax
13
asked Mar 7 at 15:30
ArianaxArianax
13
edited Mar 7 at 16:23
Arianax
asked Mar 7 at 15:30
ArianaxArianax
13
asked Mar 7 at 15:30
ArianaxArianax
13
asked Mar 7 at 15:30
ArianaxArianax
13
13
vector1[i]yields a pointer like any other. Just use->like you would for a regularClass1*. Edit : Actually, I'm just assuming. Your function isn't actually legal c++ so it's not possible to say with certainty at this point.
– François Andrieux
Mar 7 at 15:30
3
exampleFunction(vector1, int offset 5)this is invalid C++ code, please edit and clarify
– Jabberwocky
Mar 7 at 15:31
instead of vector1[i].width += offset; do vector1[i]->width += offset;
– user2320641
Mar 7 at 15:33
1
Please read Minimal, Complete, and Verifiable example for guidelines on providing complete and helpful examples. Please only share real code that you've tried yourself.
– François Andrieux
Mar 7 at 15:34
1
@Arianax Then I don't know what the problem is. Please post a MCVE (see my previous comment for a link) and then we might be able to help you.
– François Andrieux
Mar 7 at 15:41
|
show 2 more comments
vector1[i]yields a pointer like any other. Just use->like you would for a regularClass1*. Edit : Actually, I'm just assuming. Your function isn't actually legal c++ so it's not possible to say with certainty at this point.
– François Andrieux
Mar 7 at 15:30
3
exampleFunction(vector1, int offset 5)this is invalid C++ code, please edit and clarify
– Jabberwocky
Mar 7 at 15:31
instead of vector1[i].width += offset; do vector1[i]->width += offset;
– user2320641
Mar 7 at 15:33
1
Please read Minimal, Complete, and Verifiable example for guidelines on providing complete and helpful examples. Please only share real code that you've tried yourself.
– François Andrieux
Mar 7 at 15:34
1
@Arianax Then I don't know what the problem is. Please post a MCVE (see my previous comment for a link) and then we might be able to help you.
– François Andrieux
Mar 7 at 15:41
vector1[i] yields a pointer like any other. Just use -> like you would for a regular Class1*. Edit : Actually, I'm just assuming. Your function isn't actually legal c++ so it's not possible to say with certainty at this point.– François Andrieux
Mar 7 at 15:30
vector1[i] yields a pointer like any other. Just use -> like you would for a regular Class1*. Edit : Actually, I'm just assuming. Your function isn't actually legal c++ so it's not possible to say with certainty at this point.– François Andrieux
Mar 7 at 15:30
3
3
exampleFunction(vector1, int offset 5) this is invalid C++ code, please edit and clarify– Jabberwocky
Mar 7 at 15:31
exampleFunction(vector1, int offset 5) this is invalid C++ code, please edit and clarify– Jabberwocky
Mar 7 at 15:31
instead of vector1[i].width += offset; do vector1[i]->width += offset;
– user2320641
Mar 7 at 15:33
instead of vector1[i].width += offset; do vector1[i]->width += offset;
– user2320641
Mar 7 at 15:33
1
1
Please read Minimal, Complete, and Verifiable example for guidelines on providing complete and helpful examples. Please only share real code that you've tried yourself.
– François Andrieux
Mar 7 at 15:34
Please read Minimal, Complete, and Verifiable example for guidelines on providing complete and helpful examples. Please only share real code that you've tried yourself.
– François Andrieux
Mar 7 at 15:34
1
1
@Arianax Then I don't know what the problem is. Please post a MCVE (see my previous comment for a link) and then we might be able to help you.
– François Andrieux
Mar 7 at 15:41
@Arianax Then I don't know what the problem is. Please post a MCVE (see my previous comment for a link) and then we might be able to help you.
– François Andrieux
Mar 7 at 15:41
|
show 2 more comments
1 Answer
1
active
oldest
votes
for(int i = 0; i < vector1.size(); i++)
vector1[i]->width += offset;
Dereference the pointer with -> as you normally would.
answered Mar 7 at 15:33
ExaExa
3,14643554
add a comment |
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for(int i = 0; i < vector1.size(); i++)
vector1[i]->width += offset;
Dereference the pointer with -> as you normally would.
answered Mar 7 at 15:33
ExaExa
3,14643554
add a comment |
for(int i = 0; i < vector1.size(); i++)
vector1[i]->width += offset;
Dereference the pointer with -> as you normally would.
answered Mar 7 at 15:33
ExaExa
3,14643554
add a comment |
for(int i = 0; i < vector1.size(); i++)
vector1[i]->width += offset;
Dereference the pointer with -> as you normally would.
answered Mar 7 at 15:33
ExaExa
3,14643554
for(int i = 0; i < vector1.size(); i++)
vector1[i]->width += offset;
Dereference the pointer with -> as you normally would.
answered Mar 7 at 15:33
ExaExa
3,14643554
answered Mar 7 at 15:33
ExaExa
3,14643554
answered Mar 7 at 15:33
ExaExa
3,14643554
answered Mar 7 at 15:33
ExaExa
3,14643554
3,14643554
add a comment |
add a comment |
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vector1[i]yields a pointer like any other. Just use->like you would for a regularClass1*. Edit : Actually, I'm just assuming. Your function isn't actually legal c++ so it's not possible to say with certainty at this point.– François Andrieux
Mar 7 at 15:30
3
exampleFunction(vector1, int offset 5)this is invalid C++ code, please edit and clarify– Jabberwocky
Mar 7 at 15:31
instead of vector1[i].width += offset; do vector1[i]->width += offset;
– user2320641
Mar 7 at 15:33
1
Please read Minimal, Complete, and Verifiable example for guidelines on providing complete and helpful examples. Please only share real code that you've tried yourself.
– François Andrieux
Mar 7 at 15:34
1
@Arianax Then I don't know what the problem is. Please post a MCVE (see my previous comment for a link) and then we might be able to help you.
– François Andrieux
Mar 7 at 15:41