这个主要是给我自己看的,记录一下语法的使用,也可以参照了解,我已经用C++和OC代码测试过这两个文件了,如果写的有什么不足,欢迎指出
文件Array.hpp

#ifndef Array_hpp
#define Array_hpp

#include <stdio.h>
#include <iostream>

using namespace std;
namespace GYJ{
    template <class T>
    class Array {
    private:
        static const int DEFAULT_CAPACITY = 10;
        int m_size;  //元素个数
        T *arr;   //数组
        int m_capacity;  //容量
        inline void cheakIndexBeforeAdd(int index);  //添加时的验证index
        inline void cheakIndexBeforeSearch(int index);  //查找时的验证index
        void expandCapacity(int size);  //扩容
        void reduceCapacity();  //缩容
    public:
        Array();  //构造函数
        Array(const int capacity); //带参构造函数
        ~Array();  //析构函数
        int size();   //获取数组元素个数
        void add(T item);  //添加元素
        T removeIndex(int index);  //移除元素
        T elmentAtIndex(int index);
        void insert(int index,T item);  //插入元素
        T operator[](int index);  //下标
    };

    template <class T>
    Array<T>::Array() :Array(DEFAULT_CAPACITY){}

    template <class T>
    Array<T>::Array(const int capacity){
        m_capacity = capacity < DEFAULT_CAPACITY ? DEFAULT_CAPACITY : capacity;
        m_size = 0;
        arr = new T[m_capacity];
    }

    template <class T>
    Array<T>::~Array(){
        if (arr == NULL) return;
        delete[] arr;
        arr = NULL;
    }

    template <class T>
    int Array<T>::size(){
        return m_size;
    }

    template <class T>
    void Array<T>::add(T item){
        insert(m_size, item);
    }

    template <class T>
    T Array<T>::removeIndex(int index){
        cheakIndexBeforeSearch(index);
        T tmp = arr[index];
        for (int i = index + 1; i < m_size ; i++) {
            arr[i-1] = arr[i];
        }
        m_size--;
        reduceCapacity();
        return tmp;
    }

    template <class T>
    void Array<T>::insert(int index,T item){
        cheakIndexBeforeAdd(index);
        expandCapacity(m_size + 1);
        for (int i = m_size - 1; i > index; i--) {
            arr[i+1] = arr[i];
        }
        arr[index] = item;
        m_size++;
    }

    template <class T>
    T Array<T>::operator[](int index){
        cheakIndexBeforeSearch(index);
        return arr[index];
    }
    template <class T>
    T Array<T>::elmentAtIndex(int index){
        cheakIndexBeforeSearch(index);
        return arr[index];
    }
    template <class T>
    inline void Array<T>::cheakIndexBeforeAdd(int index){
        if (index < 0 || index > m_size) {
            throw "数组越界";
        }
    }
    template <class T>
    inline void Array<T>::cheakIndexBeforeSearch(int index){
        if (index < 0 || index > m_size - 1) {
            throw "数组越界";
        }
    }

    template <class T>
    void Array<T>::expandCapacity(int size){
        if(size <= m_capacity) return;
        m_capacity *= 1.8;
        T *tempArr = new T[m_capacity];
        for (int i = 0; i < m_size; i++) {
            tempArr[i] = arr[i];
        }
        delete [] arr;
        arr = tempArr;
    }

    template <class T>
    void Array<T>::reduceCapacity(){
        if (m_size > (m_capacity >> 1)) return;
        m_capacity = (m_capacity>>1) < DEFAULT_CAPACITY ? DEFAULT_CAPACITY : m_capacity>>1;
        T *tmpArr = new T[m_capacity];
        for (int i = 0; i < m_size; i++) {
            tmpArr[i] = arr[i];
        }
        delete [] arr;
        arr = tmpArr;
    }
    template <class T>
    ostream& operator<<(ostream &os,Array<T> &arr){
        os << "[";
        int size = arr.size();
        for (int i = 0; i < size; i++) {
            if(i != 0){
                os << ",";
            }
            try{
                os << arr[i];
            }catch(...){
                
            }
        }
        os << "]";
        return os;
    }

}

#endif 

头文件GYJMutableArray.h,供OC测试和使用的

NS_ASSUME_NONNULL_BEGIN
@interface GYJMutableArray : NSObject
- (int)size;
- (GYJMutableArray *)initWithCapacity:(NSInteger)capacity;
- (void)addElement:(NSObject *)element;
- (void)insertElement:(NSObject *)element atIndex:(NSInteger)index;
- (NSObject *)elementAtIndex:(NSInteger)index;
- (NSObject *)removeAtIndex:(NSInteger)index;
@end

NS_ASSUME_NONNULL_END

实现文件GYJMutableArray.mm,后缀名为mm是可以兼容c++和OC代码的

#import "GYJMutableArray.h"
#include "Array.hpp"
using namespace GYJ;
@interface GYJMutableArray()
{
    @private
    Array<NSObject *> *_mArray;
}
@end

@implementation GYJMutableArray

- (instancetype)init {
    if (self = [super init]) {
        _mArray = new Array<NSObject *>();
    }
    return self;
}
- (GYJMutableArray *)initWithCapacity:(NSInteger)capacity {
    if (self = [super init]) {
        _mArray = new Array<NSObject *>((int)capacity);
    }
    return self;
}
- (void)addElement:(NSObject *)element {
    _mArray->add(element);
}
- (void)insertElement:(NSObject *)element atIndex:(NSInteger)index {
    _mArray->insert((int)index,element);
}
- (NSObject *)elementAtIndex:(NSInteger)index {
    NSObject *obj = _mArray->elmentAtIndex((int)index);;
    return obj;
}
- (NSObject *)removeAtIndex:(NSInteger)index {
    NSObject *obj = _mArray->removeIndex((int)index);
    return obj;
}
- (int)size {
    return _mArray->size();
}
- (void)dealloc{
    delete _mArray;
}

- (NSString *)description {
    int count = _mArray->size();
    NSMutableString *mStr = [[NSMutableString alloc]init];
    [mStr appendString:@"[\n"];
    for (int i = 0; i < count; i++) {
        NSObject *element = _mArray->elmentAtIndex(i);
        NSString *str = [element description];
        [mStr appendString:str];
        if (i != count - 1) {
            [mStr appendString:@",\n"];
        }
    }
    [mStr appendString:@"]\n"];
    return mStr;
}
@end