returning a heap block by reference in c++
- by basicR
I was trying to brush up my c++ skills.
I got 2 functions:
concat_HeapVal() returns the output heap variable by value
concat_HeapRef() returns the output heap variable by reference
When main() runs it will be on stack,s1 and s2 will be on stack,
I pass the value by ref only and in each of the below functions, I create a variable on heap and concat them.
When concat_HeapVal() is called it returns me the correct output.
When concat_HeapRef() is called it returns me some memory address (wrong output). Why?
I use new operator in both the functions. Hence it allocates on heap.
So when I return by reference, heap will still be VALID even when my main() stack memory goes out of scope.
So it's left to OS to cleanup the memory. Right?
string& concat_HeapRef(const string& s1, const string& s2)
{
string *temp = new string();
temp->append(s1);
temp->append(s2);
return *temp;
}
string* concat_HeapVal(const string& s1, const string& s2)
{
string *temp = new string();
temp->append(s1);
temp->append(s2);
return temp;
}
int main()
{
string s1,s2;
string heapOPRef;
string *heapOPVal;
cout<<"String Conact Experimentations\n";
cout<<"Enter s-1 : ";
cin>>s1;
cout<<"Enter s-2 : ";
cin>>s2;
heapOPRef = concat_HeapRef(s1,s2);
heapOPVal = concat_HeapVal(s1,s2);
cout<<heapOPRef<<" "<<heapOPVal<<" "<<endl;
return -9;
}
