一维数组的实现(Array, C++版)
#ifndef __ARRAY_H__
#define __ARRAY_H__ 1
#include <iostream.h>
extern "C" { void exit(int); }
template <class T>
class Array {
private:
int FSize; //数组的大小
T *alist; //指向数组的第一个元素的指针
//为数组申请内存空间
void Allocate() {
alist = new T[FSize];
if (!alist) {
cerr << "Memory Allocation Error!" << endl;
exit(1);
}
}
public:
//构造函数
Array(int sz = 50) {
if (sz <= 0) sz = 1;
FSize = sz;
Allocate();
}
//复制构造函数：在声明数组时复制动态数组x
Array(const Array<T> &x) {
FSize = x.FSize;
Allocate();
for (int i=0; i < FSize; i++)
alist[i] = x.alist[i];
}
//析构函数
~Array() {
if (FSize > 0) {
delete [] alist;
FSize = 0;
}
}
//返回数组大小
int ListSize() { return FSize; }
//赋值运算符的重载
Array<T> & operator = (const Array<T> & x) {
if (FSize > 0) delete [] alist;
FSize = x.FSize;
Allocate();
for (int i=0; i < FSize; i++)
alist[i] = x.alist[i];
return *this;
}
//数组下标运算符[]的重载
T& operator[](int i) {
if (i < 0 || i > FSize) {
cerr << "Invalid Index!" << endl;
exit(1);
}
return alist[i];
}
//类型转换
operator T*() const {
return alist;
}
//修改数组大小
void Resize(int newSize) {
if (newSize <= 0) {
cerr << "Invalid Array Size." << endl;
return;
}
if (newSize != FSize) {
T *newList = new T[newSize];
if (!newList) {
cerr << "Memory Allocation Error !" << endl;
exit(1);
}
int n = (newSize <= FSize ? newSize : FSize);
//复制数组
for (int i=0; i < n; i++)
newList[i] = alist[i];
delete [] alist; //释放原数组所占空间
alist = newList;
FSize = newSize;
}
}
};
#endif /* !__ARRAY_H__ */
//以上为class Array的定义，请存放至array.h文件中
//以下为测试程序
#include <iostream.h>
#include <iomanip.h>
#include "array.h"
void main() {
Array<int> A(10), B(A), C; //构造函数的测试
int N, i, count=0;
cout << "List Size : " << A.ListSize() << endl;
A[5] = 30;
B[5] = 50;
cout << "A[5] = " << A[5] << endl;
cout << "B[5] = " << B[5] << endl;
A = B; //赋值运算符的测试
cout << "A[5] = " << A[5] << endl;
cout << "B[5] = " << B[5] << endl;
cout << " N = ? ";
cin >> N;
for (i = 5; i <= N; i++) {
if (count == A.ListSize())
A.Resize(count + 10); //Resize()的测试
if (i%5==0 || i%7==0)
A[count++] = i;
}
//输出数组
for (i=0; i < count;) {
cout << setw(5) << A[i++];
if (i%5 == 0) cout << endl;
}
if (i%5) cout << endl;
cout << ((int *)A)[5] << endl;
}
