C++ - List is not keeping its elements [closed] - c++

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I have 2 classes; TestUnit and TestShot.
TestUnit needs to hold a list of TestShots, however when I reference the list later on all the elements I've given it have disappeared!
TestUnit.h
#include <string>
#include <list>
#include "TestShot.h"
using namespace std;
class TestUnit
{
public:
TestUnit(string);
string getName(void);
void addShot(TestShot);
list<TestShot> getShots(void);
bool operator == (const TestUnit& tu) const { return name == tu.name; }
bool operator != (const TestUnit& tu) const { return !operator==(tu); }
private:
string name;
list<TestShot> shots;
};
TestUnit.cpp
#include "TestUnit.h"
TestUnit::TestUnit(string name)
{
this->name = name;
}
string TestUnit::getName(void)
{
return name;
}
void TestUnit::addShot(TestShot shot)
{
shots.push_front(shot);
}
list<TestShot> TestUnit::getShots(void)
{
return shots;
}
TestShot.h
#include <string>
using namespace std;
class TestShot
{
public:
TestShot(string);
string getName(void);
private:
string name;
};
TestShot.cpp
#include "TestShot.h"
TestShot::TestShot(string name)
{
this->name = name;
}
string TestShot::getName(void)
{
return name;
}
MAIN
#include <string>
#include "exports.h"
#include "TestUnit.h"
using namespace std;
// Global Variables
list<TestUnit> testUnits;
int main()
{
int nShots1 = 0;
int nShots2 = 0;
// Create Unit
TestUnit *testUnit = new TestUnit("Name");
testUnits.push_front(*testUnit);
// Create Shot and add to Unit with same 'name'
TestShot *testShot = new TestShot("Name");
for (TestUnit unit : testUnits)
{
if (unit.getName() == (*testShot).getName())
{
unit.addShot(*testShot);
nShots1 = unit.getShots().size();
}
}
// Display number of Shots for each Unit
for (TestUnit unit : testUnits)
{
nShots2 = unit.getShots().size();
std::cout << nShots1 << ", " << nShots2 << std::endl;
}
system("PAUSE");
};
Output:
1, 0
So the list realises that it's been populated straight after adding to it, but it's then empty when I need to use it.
I'm guessing this is a scope problem, but I can't seem to figure it out.
All help is much appreciated!

Answer 1

In each of your for loops, you're accessing the list elements by value, so you're effectively making a copy of what's in the list, modifying that, and then destroying it. Change your loops to look like this:
for (TestUnit &unit : testUnits)
{
if (unit.getName() == (*testShot).getName())
{
unit.addShot(*testShot);
nShots1 = unit.getShots().size();
}
}
Since you're using C++11 or later, you could also use auto instead of explicit typing (e.g., auto &unit: testUnits).