initialization with '{...}' expected for aggregate object - c++

Question

I am trying to do string parsing (and it is proving to be a huge pain). I'm getting this error: "initialization with '{...}' expected for aggregate object "
I have an element defined like this:
Element * currentBar = new Element("Bar");
I want to make an array or something to store multiple bars, so I am trying to do something like this:
Element allBars [] = new Element("Bars");
I am pretty sure this is not what I want to do, especially since I am getting this error "initialization with '{...}' expected for aggregate object "
This is a segment of my code:
if(!chartDataString.empty()){
chartData.clear();
int index = 0;
char c, c1, c2;
inputMode currentInputMode = inputMode::UNKNOWN;
Element * cur = NULL;
while(index<chartDataString.size()){
c = chartDataString[index];
c1 = chartDataString[index+1];
c2 = chartDataString[index+2];
string s;
s = c1;
Element * currentBar = new Element("Bar");
Element allBars [] = new Element("Bars");
if(c == '*'){
if(c1 == 'i'){
currentBar->addChild(Element("rehearsalLetter", "info"));
}
else{
currentBar->addChild(Element("leftDoubleBarLine", s));
index++;
}
else if(c == '['){
currentBar->addChild(Element("leftDoubleBarLine"));
}
else if(c == 'T'){
string signature = string() + c1 + '/' + c2;
currentBar->addChild(Element("timeSignature", signature));
index += 2;
}
//start a new bar
else if(c == '|'){
allBars->addChild(currentBar);
currentBar = new Element("bar");
}
And my element class just in case it's helpful:
#include <string>
#include <ostream>
#include "ArrayList.h"
class Element{
public:
Element(){}
Element( const string& _title ){
title = _title;
}
Element( const string& _title, const string& _value){
title = _title;
value = _value;
};
~Element(){};
void addChild(Element & child){
children.add(child);
}
void serialize(ostream & o ){
if( children.size() == 0 ){
o << "<" << title << ">";
o << " " << value << " ";
o << "</" << title << ">";
}else{
o << "<" << title << ">" << endl;
for( int i = 0; i < children.size(); ++i ){
children.elementAt(i).serialize(o);
}
o << "</" << title << ">" << endl;
}
}
private:
string title;
string value;
ArrayList<Element> children;
};

Answer 1

When you declare a variable Element allBars [] the compiler does expect a list of values like { Element("Bar"), Element("Foo") }. This is a static array whose size is known at compile time. So for example:
Element allBars [] = { Element("Bar"), Element("Foo") };
(Beware some compiler do require the number of element to be specified in the []).
If you want to declare a dynamic array, either you use a std::vector<Element> allBars;, which I would strongly recommend, because it cause grow and shrink without you worrying for memory allocation and deallocation. Your class should have a default constructor, a copy constructor and an assignment operator (even if generated by the compiler).
Or you use a pointer that you fill with new Element[xxx] like Element* allBars = new Element[size_of_array];, that cannot grow nor shrink and that you will have to explicitly delete using delete[] in order to call the Element destructor for every element of your array.
In both case, each Elementof the array will be initialized using the default constructor.

Answer 2

Are you trying to initialise the array with a single Element, but want it to vary in size? If so, use a vector:
vector<Element*> allBars;
vector.push_back(new Element());
If you are able to use C++11, consider using unique_ptr to ensure no memory leaks, and use emplace_back to avoid a copy when adding to the vector:
vector<unique_ptr<Element>> allBars;
vector.emplace_back(unique_ptr<Element>(new Element()));