How to pass child object in the method - c++

Question

I am parsing the child object to a method but my child data is lost. Please tell how to parse the object without loosing its data.
class A
{
int size;
std::string name;
public:
A(const std::string &name, int &size){}
virtual B *C();
}
function D()
{
int size = 10;
std::string name = "name";
return new A(name , size);
}
B *A::C(){
\\here I need name and size
}
Write now the value of size it give is 0 instead of 10 and for name it give segmentation fault
Thanks 4 the help in advance
UPDATE 1
the abstract of my code
class PrototypeAST
{
int size;
std::string FnName;
std::vector<std::string> ArgNames;
public:
PrototypeAST(const std::string &fnName, const std::vector<std::string> &argNames, int &size)
: FnName(fnName), ArgNames(argNames) {}
Function *Codegen();
void CreateArgumentAllocas(Function *F);
};
static PrototypeAST *ParsePrototype() {
int size;
std::string FnName = IdentifierStr;
getNextToken();//eat id1
std::vector<std::string> ArgNames;
if(CurTok != ')' )
{
getNextToken(); //eat int
ArgNames.push_back(IdentifierStr);
getNextToken();// eat id
while (CurTok == ',')
{
getNextToken(); //eat ,
getNextToken(); //eat int
ArgNames.push_back(IdentifierStr);
getNextToken();// eat id
}
}
// success.
getNextToken(); // eat ')'.
size = ArgNames.size();
return new PrototypeAST(FnName, ArgNames, size);
}
Function *PrototypeAST::Codegen() {
printf("\nI am in prototypeAST function\n");
// Make the function type: double(double,double) etc.
std::vector<Type*> Doubles(size,
Type::getInt1Ty(getGlobalContext()));
printf("\nI am in prototypeAST function's 1\n");
FunctionType *FT;
if(isFunInt)
FT = FunctionType::get(Type::getInt1Ty(getGlobalContext()),
Doubles, false);
else if(isFunVoid)
FT = FunctionType::get(Type::getInt1Ty(getGlobalContext()),
Doubles, false);
printf("\nI am in prototypeAST function's 2\n");
Function *F = Function::Create(FT, Function::ExternalLinkage, FnName, TheModule);
printf("\nI am in prototypeAST function's 3\n");
// If F conflicted, there was already something named 'Name'. If it has a
// body, don't allow redefinition or reextern.
if (F->getName() != FnName) {
// Delete the one we just made and get the existing one.
F->eraseFromParent();
F = TheModule->getFunction(FnName);
}
// Set names for all arguments.
unsigned Idx = 0;
for (Function::arg_iterator AI = F->arg_begin(); Idx != ArgNames.size();
++AI, ++Idx) {
AI->setName(ArgNames[Idx]);
}
printf("\nI am in prototypeAST function\n");
return F;
}

Answer 1

As others have pointed out in the comments, you should have looked at the empty constructor. You are not setting the values of the data members in the constructor. That is why the error.
PS: Do familiarize with Stack Overflow question checklist. Happy learning.

Answer 2

I have got what you wanna do. Here is the way to do it.
The empty constructor was making the problem. You can initialize your parameter with the value return by the function in following manner.
class A
{
int Size;
std::string Name;
public:
A(const std::string &name, int &size):Name(name), Size(size) {}
virtual B *C();
}
A *D()
{
int size = 10;
std::string name = "name";
return new A(name , size);
}
B *A::C(){
\\here I need name and size
}