Question

我开始学习c ++，遇到了这个编译问题。当我更改al2的大小时，我需要更改al.get(0)的大小。

完整的编译错误消息：

arraylist.cpp: In instantiation of 'void jpparl::ArrayList<T>::add(T) [with T = jpparl::ArrayList<int>]':
arraylist.cpp:90:15:   required from here
arraylist.cpp:46:33: error: use of deleted function 'jpparl::ArrayList<int>& jpparl::ArrayList<int>::operator=(const j
pparl::ArrayList<int>&)'
                 array[usedSize] = elem;
                 ~~~~~~~~~~~~~~~~^~~~~~
arraylist.cpp:5:30: note: 'jpparl::ArrayList<int>& jpparl::ArrayList<int>::operator=(const jpparl::ArrayList<int>&)' i
s implicitly deleted because the default definition would be ill-formed:
     template <class T> class ArrayList {
                              ^~~~~~~~~
arraylist.cpp:5:30: error: non-static reference member 'long int& jpparl::ArrayList<int>::usedSize', can't use default
 assignment operator
In file included from arraylist.cpp:2:0:
jppsys.cpp: In instantiation of 'static void jppsys::JPPSystem::arraycopy(T*, long int, long int, T*, long int) [with
T = jpparl::ArrayList<int>]':
jppsys.cpp:10:22:   required from 'static void jppsys::JPPSystem::expand(T**, long int, long int) [with T = jpparl::Ar
rayList<int>]'
arraylist.cpp:42:46:   required from 'void jpparl::ArrayList<T>::add(T) [with T = jpparl::ArrayList<int>]'
arraylist.cpp:90:15:   required from here
jppsys.cpp:5:78: error: use of deleted function 'jpparl::ArrayList<int>& jpparl::ArrayList<int>::operator=(const jppar
l::ArrayList<int>&)'
             for (long i = 0; i < srcEnd - srcStart; i++) dest[destStart + i] = src[srcStart + i];
                                                          ~~~~~~~~~~~~~~~~~~~~^~~~~~

还有我的源代码：

#include <iostream>
#include "jppsys.cpp"

namespace jpparl {
    template <class T> class ArrayList {
        long l = 0;
        long &usedSize = l;

        private:
            T *array;
            int step;
            long totalSize;

        public:
            ArrayList(long step) {
                this->step = step;
                totalSize = step;
                array = new T[step];
            }

            ArrayList() {
                this->step = 8;
                totalSize = step;
                array = new T[step];
            }

            void add(T elem, long index) {
                if (usedSize == totalSize) totalSize += step;

                T *tmp = new T[totalSize];
                jppsys::JPPSystem::arraycopy(array, 0, index, tmp, 0);
                jppsys::JPPSystem::arraycopy(array, index, usedSize, tmp, index + 1);
                delete[] array;
                tmp[index] = elem;
                array = tmp;

                usedSize++;
            }

            void add(T elem) {
                if (usedSize == totalSize) {
                    jppsys::JPPSystem::expand(&array, usedSize, usedSize + step);
                    totalSize += step;
                }
std::cout << usedSize << " add\n";
                array[usedSize] = elem;
                usedSize++;
            }

            void remove(long index) {
                if (usedSize == totalSize - step) totalSize -= step;

                T *tmp = new T[totalSize];
                jppsys::JPPSystem::arraycopy(array, 0, index, tmp, 0);
                jppsys::JPPSystem::arraycopy(array, index + 1, usedSize, tmp, index);
                delete[] array;
                *array = *tmp;
                usedSize--;
            }

            void remove() {
                if (usedSize == totalSize - step) {
                    jppsys::JPPSystem::expand(&array, usedSize - step, usedSize - step);
                    totalSize -= step;
                }

                usedSize--;
            }

            T get(long index) {
                return array[index];
            }

            long size() {
                return usedSize;
            }

            long getTotalSize() {
                return totalSize;
            }
    };

}

using namespace jpparl;
using namespace std;
int main() {
    ArrayList<ArrayList<int>> al;
    ArrayList<int> al2;
    al.add(al2);
    al2.add(256);
    cout << al2.size() << " " << al.get(0).size() << "\n";
}

感谢您的帮助

Answer 1

template <class T> 
class ArrayList {
        long l = 0;
        long &usedSize = l;

在您的类中具有引用会隐式删除您的operator=，您需要重写它，而且我也不确定为什么要对类变量进行私有引用吗？如果删除引用并仅使用l变量，它将起作用。

还有#include "jppsys.cpp"

不包括.cpp个文件。

错误：当我尝试使用引用时使用删除的功能

1 个答案: