Sorted list: must have class/struct/union - c++

Question

so i have been working on a code for over two weeks and its not going too well. here are the instructions and the code is below it, as well as errors:
Task 1: Create one instance of this class. (the sorted list; he also had other instructions on HOW to start the code, but its already been done by me below in the code such as typedef...) You also need to read in data from one data file: float.dat, which contains the following numbers:
5.5
6.2
7.1
8.0
9.0
10.0
1.0
2.0
3.3
4.4
Data in float.dat contains floating numbers, which should be inserted into the object of SortedList. Note that you do not have any prior knowledge about data values in float.dat, but we assume that there are 10 elements in the data file.
Task 2: Use GetNextItem( ) to print out all the elements in the list in sorted sequence on computer screen.
Task 3: Use GetNextItem( ) to output all the elements in the list in sorted sequence onto a data file, output.dat.
Task 4: Design your test cases to demonstrate InsertItem( ), DeleteItem( ) and RetrieveItem( ) are working as expected.
here is the code:
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
#define MAX_ITEMS 10
typedef float ItemType;
class SortedList
{
private:
int length;
ItemType values[MAX_ITEMS];
int currentPos;
enum RelationType { LESS, GREATER, EQUAL };
public:
SortedList() {length = 0; currentPos = -1;}
int getLength() {return length;}
RelationType ComparedTo(ItemType x)
{
if (length > x.getLength())
return LESS;
else if (length == x.getLength())
return GREATER;
else
return EQUAL;
}
void MakeEmpty() {length = 0;}
void InsertItem(ItemType x)
{
int first = 0, last = length --;
bool moreToSearch = (first <= last);
int location = 0;
int midpoint= (first + last) / 2;
while (moreToSearch)
{
switch (x.ComparedTo(values[location]))
{
case LESS: //search in 1st half
moreToSearch = (first <= last);
break;
case GREATER:
location++;
moreToSearch = (location < length);
break;
}
}
for (int index = length; length > location; index--)
{
values[index] = values[index - 1];
}
values[location] = x;
length++;
}
void DeleteItem(ItemType x)
{
int location = 0;
while (x.ComparedTo(values[location]) != EQUAL)
location++;
for (int index = location ++; index < length; index++)
values[index --] = values[index];
length--;
}
void RetrieveItem(ItemType &x, bool & found)
{
int midpoint;
int first = 0, last = length - 1;
bool moreToSearch = (first <= last);
found = false;
int index = 0;
while (moreToSearch && !found)
{
midpoint = (first + last) / 2;
switch (x.ComparedTo(values[index++]))
{
case LESS: //search in 1st half
moreToSearch = (first <= last);
last = midpoint - 1;
break;
case GREATER: //Search in 2nd half
first = midpoint + 1;
moreToSearch = (first <= last);
break;
case EQUAL: //x has been found
found = true;
break;
}
}
}
int LengthIs() {return length;}
void ResetList() {currentPos = -1;}
bool IsFull()
{
if (length < 9)
return false;
else
return true;
}
void GetNextItem(ItemType &x)
{
currentPos++;
x = values[currentPos];
cout << x;
}
};
int main()
{
SortedList x;
ifstream inFile; ofstream output;
string line;
bool allAboutLists;
int i = 0;
int size = 0;
inFile.open("float.txt");
float values[10];
while (!inFile.eof()) // write or read data from inFile into values
{
inFile >> values[i];
i++;
size++; // this will count how many values there are in the array
x.InsertItem(values[i]);
++i;
}
x.ResetList();
cout << "The following is the list that's been made:" << endl << endl;
x.InsertItem(64);
//x.printlist();
cout << endl;
x.DeleteItem(64);
//x.printlist();
x.RetrieveItem(7.1, allAboutLists);
cout << endl;
cout << endl << "The length is: "; x.LengthIs(); cout << endl;
cout << "Is the list full?: " << boolalpha << x.IsFull() << endl;
cout << "The next item is: ";
for (int i = 0; i < 10; i++)
{
cout << x.GetNextItem << endl;
}
x.ResetList();
inFile.close();
output.open("output.txt");
for (int f = 0; f < 10; f++)
{
output << x.GetNextItem << endl;
}
system("pause");
return 0;
}
and the compiler keeps saying this:
(25) error C2228: left of '.getLength' must have class/struct/union [they mean the x. its red lined under, same for the rest of those left of etc..]
(27) error C2228: left of '.getLength' must have class/struct/union
(44) error C2228: left of '.ComparedTo' must have class/struct/union
(66): error C2228: left of '.ComparedTo' must have class/struct/union
-and also, 7.1 in main has something about refernce type mistake.
I am in extereme hurry as i have been working on it for 2 weeks now and its driving me crazy ! I have the code done as seen and more than wnough and just need to know what to change exactly because I am following everything I have been searching and researching yet its no good. so precise details or code specifically taken from mine and fixed would be appreciated.
Thanks!

Answer 1

You are passing x as ItemType which is a float.
float doesn't have those methods... looks like you wanted to pass it as a SortedList

Answer 2

The compare function needs two parameters in order to do a compare. Instead of ComparedTo, you may want to call it CompareToLocation.
RelationType CompareToLocation(ItemType x, size_t location){
if(x < values[location]) return LESS;
if(x == values[location]) return EQUAL;
return GREATER;}
An example usage would be:
result = CompareToLocation(x, location);
// ...

Answer 3

You defined ComparedTo as a method for SortedList, yet everytime you call that function, you call it on ItemType objects, which are actually floats.
As you can see in the definition of the method, you are trying to use, once again, SortedList methods on float Objects:
RelationType ComparedTo(ItemType x)
{
if (length > x.getLength())
return LESS;
else if (length == x.getLength())
return GREATER;
else
return EQUAL;
}
Your problem is not really a compiling one, but a conceptual one, since you don't seem to grasp what your are actually coding.
I'd recommend have your declarations and implementations separate, so you can see at a glance how does your class work.
Your class declaration should look something like this:
class SortedList
{
private:
int length;
ItemType values[MAX_ITEMS];
int currentPos;
enum RelationType { LESS, GREATER, EQUAL };
public:
SortedList();
int getLength();
RelationType ComparedTo(ItemType x) ;
void MakeEmpty();
void InsertItem(ItemType x) ;
void DeleteItem(ItemType x);
void RetrieveItem(ItemType &x, bool & found);
int LengthIs();
void ResetList();
bool IsFull();
void GetNextItem(ItemType &x);
};
You should focus on each method, making clear what each one of them is trying to achieve, and what does it need to achieve it (parameters).
For example:
RelationType ComparedTo(ItemType x) ;
Your SortedList class has this function, which receives an ItemType (float) as a parameter.
What is this trying to achieve? How do you compare a whole ordered list to a single element?
How can a single number be greater, less or EQUAL to a set of numbers?
Maybe what you really want to do is compate parameter X with an element inside the list?
If this is the case, how do you know which element in the list must be compared to parameter X? You should add another parameter telling you which element inside your ordered list to compare X to.
I quess this doesn't really solve your problem, but at least I hope this helps you understand better what your problem is.