所以，对于一个赋值，我创建了一个模拟通常在C ++中找到的Vector质量的类，并且我试图重载赋值运算符（=），以便可以在两个“向量”之间执行深度复制，但我一直在遇到问题。我意识到我的代码有点半生不熟，但有人可以帮助我吗？
//stdafx.h
#pragma once
#include "targetver.h"
#include <iomanip>
#include <array>
#include <stdio.h>
#include <tchar.h>
#include <string>
#include <fstream>
#include <iostream>
using namespace std;
//Vector.h
class Vector
{
double* arr; // pointer to the first element of this vector
int cap; // number of elements arr can hold (i.e. size of underlying array)
int sz;// size of this vector
// The increase_capacity function
// Purpose: Dincrease capacity of vector
// Parameters: new capacity of vecoter
// Returns: none
void increase_capacity(int new_cap)
{
// Increases the capacity of the underlying array to be sz. If sz
// is smaller than the current capacity then nothing is done.
double* new_arr = new double[new_cap]; // allocate a new array
for (int i = 0; i < cap; ++i)
{ // copy old vector into new one
new_arr[i] = arr[i];
}
cap = new_cap;//set new capacity of vector
delete[] arr;//delete old vector from memory
arr = new_arr;//set old vector to new vector
}
public:
// The non-parameterized constructer
// Purpose: create an empty vector with capacity of 2 and size of 0
// Parameters: none
// Returns: vector
Vector();
// The Parameterized Constructer
// Purpose: create an empty vector with capacity of n and size of 0
// Parameters: int n
// Returns: vector
Vector(int n);
// The size function
// Purpose: get current size of vector
// Parameters:
// Returns: vector size as an int
int size() const;
// The push_back function
// Purpose: push back values into vector
// Parameters: int n
// Returns: none
void push_back(int n);
// The capacity function
// Purpose: get current capacity of vector
// Parameters: none
// Returns: capacity of vector as a double
double capacity();
// The at function
// Purpose: get value stored in vector at index n
// Parameters: int n
// Returns: value stored at index n as a double
double at(int n) const;
// The clear function
// Purpose: clear and reset vector to an empty vector with capacity of n and size of 0
// Parameters: none
// Returns: none
void clear();
const Vector& Vector::operator=(const Vector & rho);
friend ostream& operator<<(ostream& os, const Vector& vctr);//allows overloaded insertion operator
// The destructor
// Purpose: clears data on heap and prevents memory leaks
// Parameters: none
// Returns: none
~Vector();
};
//Vector.cpp
#include "stdafx.h"
#include "Vector.h"
//const int to hold value of 2
const int DUO = 2;
//const int to hold badIdex throw value
const int BAD = -6;
// The non-parameterized constructer
// Purpose: create an empty vector with capacity of 2 and size of 0
// Parameters: none
// Returns: vector
Vector::Vector()
{
arr = new double[DUO];
cap = 2;
sz = 0;
}
// The Parameterized Constructer
// Purpose: create an empty vector with capacity of n and size of 0
// Parameters: int n
// Returns: vector
Vector::Vector(int n)
{
arr = new double[n];
cap = n;
sz = 0;
}
// The destructor
// Purpose: clears data on heap and prevents memory leaks
// Parameters: none
// Returns: none
Vector::~Vector()
{
delete[] arr;
}
// The size function
// Purpose: get current size of vector
// Parameters:
// Returns: vector size as an int
int Vector::size() const
{
return sz;
}
// The push_back function
// Purpose: push back values into vector
// Parameters: int n
// Returns: none
void Vector::push_back(int n)
{
if (sz >= cap) increase_capacity(DUO * cap);
arr[sz] = n;
++sz;
}
// The capacity function
// Purpose: get current capacity of vector
// Parameters: none
// Returns: capacity of vector as a double
double Vector::capacity()
{
return cap;
}
// The at function
// Purpose: get value stored in vector at index n
// Parameters: int n
// Returns: value stored at index n as a double
double Vector::at(int n) const
{
if (arr[n] >= 0)
{
return arr[n];
}
else
{
throw BAD;
}
}
// The clear function
// Purpose: clear and reset vector to an empty vector with capacity of n and size of 0
// Parameters: none
// Returns: none
void Vector::clear()
{
delete[] arr;
arr = new double[DUO];
cap = 2;
sz = 0;
}
//Driver.cpp
#include <iostream>
#include "Vector.h"
#include "Vector.cpp"
#include "stdafx.h"
using namespace std;
// the printV function
// used to test the copy constructor
// parameter: a Vector object
void printV(Vector& v);
// The overloaded stream insertion function
//Purpose: allow cout to print objects
// Parameters: pointer to ostream object, pointer to Money object
// Returns: os object
ostream& operator<<(ostream& os, const Vector& vctr)
{
os << vctr;//allow printing of objects from Money class
return os;//return printed information
}
const Vector& Vector::operator=(const Vector & rho)
{
// TODO: insert return statement here
// test for self assignment
if (this == &rho)
return *this;
sz = rho.size;
// clean up array in left hand object (this)
delete[] this;
// create a new array big enough to hold right hand object's data
lho.size = rho.size;
this->lho = new char[sz];
// copy the data
for (int i = 0; i < sz; i++)
{
this->lho[i] = rho.lho[i];
}
// return this object
return *this;
}
int main( )
{
cout << "\nCreating a vector Sam of size 4.";
Vector sam(4);
cout << "\nPush 12 values into the vector.";
for (int i = 0; i < 12; i++)
sam.push_back(i);
cout << "\nHere is sam: ";
cout << sam;
cout << "\n---------------\n";
cout << "\nCreating a vector Joe of size 4.";
Vector joe(4);
cout << "\nPush 6 values into the vector.";
for (int i = 0; i < 6; i++)
joe.push_back(i * 3);
cout << "\nHere is joe: ";
cout << joe;
cout << "\n---------------\n";
cout << "\nTest the overloaded assignment operator \"joe = sam\": ";
joe = sam;
cout << "\nHere is sam: ";
cout << sam;
cout << "\n---------------\n";
cout << "\nHere is joe: ";
cout << joe;
cout << "\n---------------\n";
// pass a copy of sam by value
printV(sam);
cout << endl;
system("PAUSE");
return 0;
}
void printV(Vector& v)
{
cout << "\n--------------------\n";
cout << "Printing a copy of a vector\n";
cout << v;
}
答案 0 :(得分：0)
Error (active) identifier "lho" is undefined
导致此错误的原因是您使用的是未在任何位置定义的变量lho。您需要定义它或使用不同的变量。