Please solve these errors. I'm using dev++ compiler [closed] - c++

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Kindly tell me what's wrong with the code. It is showing many errors. The error statements and problem statement is given below:
First error is in the overloaded dereference operator. It says pmemory was not declared in this scope.
2nd error is in the main function where I use
ptrFloat ptr1 = &var1;
it shows error "conversion from 'Float' to non-scalar type 'ptrFloat' requested".
And in the next line of above mention statement save error..
in next line it show that (no match for operator <<) .
and in the very next line it show the same error as above.(no match for operator).
And at last it show again the same error that (no match for operator)
The question statement is given below:
Remember fmem_top is an index to fmemory which points to the next available place where a float value can be stored. And pmem_top is the similer index to pmemory.
Create a class called Float . We’ll use it to model numbers of type float that are stored in fmemory instead of real memory. The only instance data in Float is its own “address”; that is, the index where its float value is stored in fmemory. Call this instance variable addr. Class Float also needs two member functions. The first is a one-argument constructor to initialize the Float with a float value. This constructor stores the float value in the element of fmemory pointed to by fmem_top , and stores the value of fmem_top in addr . This is similar to how the compiler and linker arrange to store an ordinary variable in real memory. The second member function is the overloaded & operator. It simply returns the pointer (really the index, type int ) value in addr .
Create a second class called ptrFloat . The instance data in this class holds the address(index) in pmemory where some other address (index) is stored. A member function initializes this “pointer” with an int index value. The second member function is the overloaded * (dereference, or “contents of”) operator. Its operation is a tad more complicated.
It obtains the address from pmemory , where its data, which is also an address, is stored. It then uses this new address as an index into fmemory to obtain the float value pointed to by its address data.
float& ptrFloat::operator*()
{
return fmemory[pmemory[addr]];
}
#include<iostream>
#include<conio.h>
using namespace std;
class Float
{
protected:
float *fmem_top;
float **addr;
float fmemory[10];
public:
Float(float a)
{
fmem_top=fmemory;
addr=&fmem_top;
*fmem_top=a;
fmem_top++;
}
Float operator & ()
{
return *fmem_top;
}
};
class ptrFloat: public Float
{
private:
int *pmem_top;
int pmemory[10];
public:
ptrFloat(int abc) : Float(abc)
{
pmem_top=pmemory;
*pmem_top=abc;
pmem_top++;
}
ptrFloat operator * ()
{
return fmemory[pememory[addr]];
}
};
int main ()
{
Float var1 = 1.234;
Float var2 = 5.678;
ptrFloat ptr1 = &var1;
ptrFloat ptr2 = &var2;
cout<<"*ptr1 = "<< *ptr1;
cout<<"*ptr2 = "<< *ptr2;
*ptr1 = 7.123;
*ptr2 = 8.456;
cout<<"*ptr1 = "<< *ptr1;
cout<<"*ptr2 = "<< *ptr2;
getch();
return 0;
}

Answer 1

I'm not sure what's going on here, but this is what Clang has to say:
prog.cc:33:48: error: array subscript is not an integer
ptrFloat operator*() { return fmemory[pmemory[addr]]; }
^~~~~
There's a typo in the line here - you'd written pememory. But addr is a float**.
prog.cc:40:12: error: no viable conversion from 'Float' to 'ptrFloat'
ptrFloat ptr1 = &var1;
^ ~~~~~
ptrFloat is a class derived from Float, not a Float*.
What's your intent with this code?
As an aside, the clang compiler has great and helpful error messages. If you don't/can't install clang on your computer - I think it's a pfaff to set it up on Windows, I don't know - you can quickly test your code on an online compiler such as Wandbox and see if clang's output gives better clues. Here's your code running there - I had to strip out conio.h and getch as they're Windows-only: http://melpon.org/wandbox/permlink/4iCa61Rqysqc7Lpl

Answer 2

The first error is a typo you wrote pememory.
The second error appears because you didn't code any transformation between Float and ptrFloat.
You should add a copy constructor to Float:
Float(const Float& a) : Float(*a.fmem_top) {}
And then a conversion constructor to ptrFloat:
ptrFloat(Float a) : Float(a) {
pmem_top=pmemory;
*pmem_top=abc;
pmem_top++;
}
PS: your code has a lot of problems. I don't really get what you are trying to do, but, for instance, you can't have float typed variables as array subscripts.