Compile-time error building a simple partial array class in C++ - c++

Question

I'm having trouble getting my Partial Arrays class to compile. In one of my member functions I call for a previous member function and get the error "member reference base type 'ITEM_TYPE [255]' is not a structure or union".
I'm not entirely sure that my member variable declarations are up to snuff, as this is my first time dealing with arrays in C++.
Here is my header:
#ifndef PARTIALARRAY_H
#define PARTIALARRAY_H
#include <iostream>
#include <string.h>
using namespace std;
typedef int ITEM_TYPE;
ITEM_TYPE const MAX = 255;
class PartialArray
{
public:
//-----------------------------------------ctors:-----------------------------------------
PartialArray();
PartialArray(ITEM_TYPE MAX, int numUsed);
//-----------------------------------------member functions:-----------------------------------------
void PrintArray(int a[], int numUsed);
int Search(int a[], int numUsed, ITEM_TYPE key);
int Append(ITEM_TYPE appendMe);
int ShiftRight(int shiftHere);
int ShiftLeft(int shiftHere);
int InsertBefore(ITEM_TYPE insertThis, int insertHere);
int InsertAfter(ITEM_TYPE insertThis, int insertHere);
int Delete(int deleteHere);
string ErrorDescr(int failCode);
private:
//-----------------------------------------member vars:-----------------------------------------
ITEM_TYPE a[MAX];
int numUsed;
};
#endif // PARTIALARRAY_H
And my class declaration (NOTE: the error function and return values are not complete, so those can be ignored):
#include "partialarray.h"
#include <iostream>
#include <string.h>
using namespace std;
//-----------------------------------------ctors:-----------------------------------------
PartialArray::PartialArray()
{
numUsed=0;
}
PartialArray::PartialArray(ITEM_TYPE MAX, int numUsed)
{
numUsed = MAX;
}
//-----------------------------------------member functions:-----------------------------------------
//Prints the array up to its last used element
void PartialArray::PrintArray(ITEM_TYPE a[], int numUsed)
{
for(int i=0; i<numUsed; i++)
{
cout << a[i] << " ";
}
cout << endl;
}
//Searches the array for a particular value and returns the index at which the value first appears
int PartialArray::Search(ITEM_TYPE a[], int numUsed, ITEM_TYPE key)
{
for(int i=0; i<numUsed; i++)
{
if(a[i]==key)
{
return i;
break;
}
else
;
}
return -1; //placeholder for error
}
//Takes a number and appends it to the end of the array after the last interesting element
int PartialArray::Append(ITEM_TYPE appendMe)
{
if(a[numUsed==0])
a[numUsed] = appendMe;
else
return 0; //placeholder for error
return 1; //placeholder for error
}
//Shifts all elements of the array to the right starting at a particular index
int PartialArray::ShiftRight(int shiftHere)
{
ITEM_TYPE save = a[numUsed-1];
for(int i=numUsed; i>=shiftHere; i--)
{
a[i] = a[i-1];
}
a[0] = save;
return 1; //error placeholder
}
//Shifts all elements of the array to the left starting at a particular index
int PartialArray::ShiftLeft(int shiftHere)
{
ITEM_TYPE save = a[0];
for(int i=shiftHere; i<numUsed; i++)
{
a[i] = a[i+1];
}
a[numUsed-1] = save;
return 1; //error placeholder
}
//Takes a number and a position and inserts the number at that position in the array shifting the elements to the right
int PartialArray::InsertBefore(ITEM_TYPE insertThis, int insertHere)
{
a.ShiftRight(insertHere);
a[insertHere] = insertThis;
return 1; //error placeholder
}
//Takes a number and a position and inserts the number at that position in the array shifting the elements to the left
int PartialArray::InsertAfter(ITEM_TYPE insertThis, int insertHere)
{
a.ShiftLeft(insertHere);
a[insertHere] = insertThis;
return 1; //error placeholder
}
//Takes a position and removes that item from the array, shifting all the elements to the left
int PartialArray::Delete(int deleteHere)
{
a[deleteHere] = 0;
a.ShiftLeft(deleteHere);
return 1; //error placeholder
}
string PartialArray::ErrorDescr(int failCode)
{
switch(failCode)
{
case 1:
return "ERROR: etc";
break;
case 2:
return "ERROR: etc";
break;
case 3:
return "ERROR: etc";
break;
case 4:
return "ERROR: etc";
break;
case 5:
return "ERROR: etc";
break;
default:
return "ERROR: etc";
break;
}
}
I have previously built a Rationals class, and I felt solid on that material, but doing something similar with arrays has proven to be a major headache. Any help would be much appreciated!

Answer 1

Most of your code seems ok. However, a is a C-style array, and thus has no member functions.
Thus, the following lines are incorrect:
a.ShiftRight(insertHere);
...
a.ShiftLeft(insertHere);
As you try to use this array with a syntax meaningul only for struct or class variables, the compiler issues here the error message you observe: "member reference base type 'ITEM_TYPE [255]' is not a structure or union"