C++ Compiler errors

Question

I'm writing a c++ stack and queue implementation program, I finished the stack part, but when compiling I'm getting these errors

arrayListImp.cpp:18:19: error: expected unqualified-id
                arrayList[++top]= x;
                                ^
arrayListImp.cpp:28:13: error: 'arrayList' does not refer to a value
                itemPoped=arrayList[top];
                          ^
./arrayList.h:3:7: note: declared here
class arrayList{
      ^
arrayListImp.cpp:35:9: error: 'arrayList' does not refer to a value
        return arrayList[top];
               ^
./arrayList.h:3:7: note: declared here
class arrayList{
      ^
arrayListImp.cpp:46:9: error: 'arrayList' does not refer to a value
                cout<<arrayList[i]<<endl;
                      ^
./arrayList.h:3:7: note: declared here
class arrayList{
      ^
4 errors generated.

Here is the header file

#ifndef ARRAYLIST_H

class arrayList{

public:
    arrayList();
    static const int maxSize = 10;
    int array[10];
};

class stack : public arrayList{

public:
    stack();    
    void push(int x);
    void pop();
    int Top();
    int isEmpty();
    void print();
    int x;
    int top;
    int itemPoped;
    int i;
};

#define ARRAYLIST_H
#endif

arrayListImp.cpp

#include <iostream>
#include "arrayList.h"
using namespace std;

//Stack implementation

stack::stack(){

    top = -1;
}

void stack::push(int x){

    if (top == maxSize -1){
        cout<<"Stack overflow"<<endl;
    }
    else{
        arrayList[++top]= x;
        cout<<x<<", is pushed on to the stack"<<endl;
    }
}

void stack::pop(){
    if (top == -1){
        cout<<"Stack underflow"<<endl;
    }
    else{
        itemPoped=arrayList[top];
        top--;
        cout<<itemPoped<<", is poped from the stack"<<endl; 
    }
}

int stack::Top(){
    return arrayList[top];
}

int stack::isEmpty(){
    if (top == -1) return 1;
    return 0;
}

void stack::print(){
    cout<<"Stack: "<<endl;
    for (i = 0; i<=top; i++){
        cout<<arrayList[i]<<endl;

    }
}

arrayListUse.cpp

#include <iostream>
#include "arrayList.h"
using namespace std;


int main()
{
    //Stack testing
    stack S;
    S.push(1);S.print();
    S.push(2);S.print();
    S.push(3);S.print();
    S.pop();S.print();
    S.push(4);S.print();

    //Queue testing



    return 0;
}

Can you please point out to what I'm doing wrong here?

Answer 1

You always have written

arrayList[...]

what is the name of your class but reading the code it seems like you wanted to write

array[...]

which would access the data.

Answer 2

You should just read your error messages.

1. You should use array instead of arrayList , which is the name of the class. So just refer to the variable instead.

   The error message you got is something like

    test.cpp: In member function 'void stack::push(int)': test.cpp:44:18: error: expected unqualified-id before '[' token arrayList[++top]= x; ^ 

   When you check the line, you immediately see what is wrong there.

2. You declare a constructor arrayList::arrayList() , but you do not define it. Either you can drop the declaration, or you should implement it in the cpp-file.

    arrayList::arrayList() { // do some initialization } 

   The error message you got is something like

    /tmp/cc4y06YN.o:test.cpp:function stack::stack(): error: undefined reference to 'arrayList::arrayList()' 

   The code could compile, but it did not link. So all declarations may be correct, but a symbol was missing. This is usually the case when you declared something you referred to, but you never defined it.