#include<iostream>
#include<vector>
#include<map>
#include<string>
#include<cstring>
#include<cstdio>
#include<algorithm>
#include<set>
#include<queue>
#include<unordered_map>
#include<cmath>
using namespace std;
class CArray
{
int st = 32;
int size, temp;
int* ptr;
public:
CArray(int s = 0);
CArray(CArray& a);
~CArray();
void push_back(int v);
void resize(int v);
void Resize(int v);
CArray& operator=(const CArray& a);
int length() { return max(size,temp); };
int& operator [](int i)
{
return ptr[i];
}
};
CArray::CArray(int s):size(s)
{
if (s == 0)
ptr = NULL;
else
ptr = new int[s];
}
CArray::CArray(CArray& a)
{
if (!a.ptr)
{
ptr = NULL;
size = 0;
return;
}
ptr = new int[a.size];
memcpy(ptr, a.ptr, sizeof(int) * a.size);
size = a.size;
}
CArray::~CArray()
{
if (ptr) delete[]ptr;
}
CArray& CArray::operator=(const CArray& a)
{
if (ptr == a.ptr)
return *this;
if (a.ptr == NULL)
{
if (ptr) delete[]ptr;
ptr = NULL;
size = 0;
return *this;
}
if (size < a.size)
{
if (ptr) delete[]ptr;
ptr = new int[a.size];
}
memcpy(ptr, a.ptr, sizeof(int) * a.size);
size = a.size;
return *this;
}
void CArray::resize(int v)
{
int* temptr = new int[v];
memcpy(temptr, ptr, sizeof(int) * size);
delete[]ptr;
ptr = temptr;
if (v > size)
{
temp = size;
while (temp < v)
{
ptr[temp++] = 0;
}
}
}
void CArray::Resize(int v)
{
int* temptr = new int[v];
memcpy(temptr, ptr, sizeof(int) * size);
delete[]ptr;
ptr = temptr;
}
void CArray::push_back(int v)
{
if (ptr)
{
if(size<st)
ptr[size++] = v;
else
{
st = st * 2;
Resize(st);
ptr[size++] = v;
}
}
else
{
ptr = new int[st];
ptr[size++] = v;
}
}
int main()
{
CArray a, a2, a3, a5;
for (int i = 0; i < 123; i++)
{
a.push_back(i);
}
a2 = a;
for (int i = 0; i < a2.length(); i++)
{
cout << a2[i] << " ";
}
cout << endl;
a2 = a3;
for (int i = 0; i < a2.length(); i++)
{
cout << a2[i] << " ";
}
cout << endl;
a[3] = 100;
CArray a4(a);
for (int i = 0; i < a4.length(); i++)
{
cout << a4[i] << " ";
}
cout << endl;
a5.resize(7);
a5[5] = 1;
for (int i = 0; i < a5.length(); i++)
{
cout << a5[i] << " ";
}
return 0;
}`
