Float prints a large, weird value - c++

Question

So, I create a State class. In that State class's create function, it creates a StateVisual class by calling the StateVisual class's create function, passing itself as a parameter. (The parameter is a reference so that there is no copying). The StateVisual then sets the parameter (The State Instance), as it's parent variable, which is a pointer of a State type.
In the StateVisual's create function, everything works fine. However, when you get to it's update method, and try to print it's parent size, it prints some weird value.
#ifndef STATE_H
#define STATE_H
#include "cocos2d.h"
class StateVisual;
class State {
public:
State();
~State();
static State create();
StateVisual *visual;
float size;
void setSize(float);
void update(float);
private:
cocos2d::Scheduler* _scheduler;
};
#endif
StateVisual.cpp
#ifndef STATE_VIS_H
#define STATE_VIS_H
#include "cocos2d.h"
#include "State.h"
class StateVisual : public cocos2d::Sprite {
public:
StateVisual();
~StateVisual();
// create a visual
State* parent;
static StateVisual* create(State& parent);
cocos2d::Label* label;
void setSize(float);
void update(float);
private:
bool _activated;
float _size;
};
#endif
State.cpp
#include "State.h"
#include "GameScene.h"
State::State() : size(0) {
CCLOG("Created");
}
State::~State() {
}
void State::setSize(float newSize) {
size = newSize;
CCLOG("%f, %f", newSize, size);
}
void State::update(float dt) {
}
State State::create() {
State state;
state.visual = StateVisual::create(state);
cocos2d::SEL_SCHEDULE ss;
return state;
}
StateVisual.cpp
#include "StateVisual.h"
#include "GameScene.h"
using namespace cocos2d;
StateVisual::StateVisual() : parent(nullptr) {
CCLOG("New STATE VISUAL!");
}
StateVisual::~StateVisual() {
}
void StateVisual::setSize(float size) {
setContentSize(Size(size, size));
if (size > 30) {
label->setSystemFontSize(size*.1);
label->setOpacity(255);
}
else {
label->setOpacity(0);
}
}
void StateVisual::update(float dt) {
cocos2d::MathUtil::smooth(&_size, parent->size, dt, .2);
setSize(_size);
CCLOG("%f, %f", _size, (*this->parent).size);
}
StateVisual* StateVisual::create(State &parent) {
StateVisual* visual(new StateVisual());
if (visual->initWithFile("Circle.png"))
{
visual->setSize(200);
visual->_size = 200;
visual->parent = &parent;
visual->parent->setSize(20);
CCLOG("PARENT SIZE: %f", visual->parent->size);
visual->autorelease();
visual->scheduleUpdate();
return visual;
}
CC_SAFE_DELETE(visual);
return NULL;
}
It outputs:
Created
New STATE VISUAL!
cocos2d: fullPathForFilename: No file found at /cc_2x2_white_image. Possible
missing file.
20.000000, 20.000000
PARENT SIZE: 20.000000
500.000000, 500.000000
cocos2d: QuadCommand: resizing index size from [-1] to [2560]
168.058044, -107374176.000000 <-- Those are the weird values it prints
155.130508, -107374176.000000
The program '[1464] State.exe' has exited with code 0 (0x0).

Answer 1

0xCCCCCCCC, a typical value used to fill uninitialized memory in Debug builds, interpreted as a 32-bit float, equals -107374176.000000. You're printing an uninitialized float value.

Answer 2

State State::create() {
State state;
state.visual = StateVisual::create(state);
cocos2d::SEL_SCHEDULE ss;
return state;
}
At the end of this function the local object state is destroyed a copy ois made (or moved to a new object). Which means any pointer to the address &state is invalid after the end of State::create
visual->parent = &parent; // parent = state object on stack
Because of this line visual->parent is now dangling.
Those weird values are the random content of you thread stack...
What you should do is use shared pointers for state\parent.

Answer 3

void StateVisual::update(float dt) {
cocos2d::MathUtil::smooth(&_size, parent->size, dt, .2);
setSize(_size);
CCLOG("%f, %f", _size, (*this->parent).size);
Why do you use parent->size in 1 row of function and (*this->parent).size in third?
Why don't you use getters and setters?
Why haven't you shown header files?
Why haven't you prepared minimal example (like just parent-child logic and sizes without labels, positions etc.?
What is this suposed to do? StateVisual* visual(new StateVisual());
If visual is automatic variable, i think it should look loke StateVisual visual(new StateVisual()); otherwise shouldn't it be StateVisual* visual = new StateVisual(new StateVisual()); Also are you sure you want to pass new StateVisual object into constructor of StateVisual?