使用包含数组指针的类重载+运算符（C ++） [英] Overloading + operator with classes containing array pointers (C++)
问题描述
我目前正在写一个多项式类来练习操作符重载。我已经成功重载流提取和插入操作符，但我有一些麻烦与+运算符。
I am currently writing a "Polynomial" class in order to practice Operator Overloading. I have successfully overloaded the stream extraction and insertion operators, but I am having some trouble with the "+" operator.
我的类有一个私有指针，继续在构造函数中创建一个数组。我理解如何用一个复杂的类来重载+运算符，例如，但我很困惑这个程序。
My class has a private pointer that proceeds to create an array in the constructor. I understand how one would overload the "+" operator with a complex number class, for example, but I'm getting confused with this program.
指导寻找解决方案将非常感谢。
谢谢。
Guidance in finding a solution would be greatly appreciated. Thank you.
#include<iostream>
#include<stdexcept>
using namespace std;
#ifndef POLYNOMIAL_H
#define POLYNOMIAL_H
class Polynomial
{
friend istream& operator>>(istream& in, Polynomial& p);
friend ostream& operator<<(ostream& out, const Polynomial& p);
public:
Polynomial(int = 10);
~Polynomial();
void assignExponent();
Polynomial operator+(const Polynomial& other);
private:
int SIZE;
int *exponents;
int *polyPtr; //***************
};
#endif
//CONSTRUCTOR
Polynomial::Polynomial(int arraySize)
{
if(arraySize > 0)
SIZE = arraySize;
else
{
cout << "Array size must be greater than 0. Program will now "
<< "Terminate..." << endl;
system("pause");
exit(0);
}
polyPtr = new int[SIZE]; //*********************
exponents = new int[SIZE];
for(int i = 0; i<SIZE; i++)
polyPtr[i] = 0;
assignExponent();
};
//DESTRUCTOR
Polynomial::~Polynomial() //******************
{
delete [] polyPtr;
};
//STREAM INSERTION
istream& operator>>(istream& in, Polynomial& p)
{
for(int i = 0; i<p.SIZE; i++)
{
in >> p.polyPtr[i]; //*************
}
return in;
};
//STREAM EXTRACTION
ostream& operator<<(ostream& out, const Polynomial& p)
{
int exponent;
for(int i = 0; i<p.SIZE; i++)
{
exponent = (p.SIZE - 1) - i;
if(p.polyPtr[i] != 1)
{
if(exponent > 0 && exponent != 1)
out << p.polyPtr[i] << "x^" << exponent << " + ";
if(exponent == 1)
out << p.polyPtr[i] << "x" << " + ";
if(exponent == 0)
out << p.polyPtr[i];
}
//In order to not display coefficient if = 1
else
{
if(exponent > 0 && exponent != 1)
out << "x^" << exponent << " + ";
if(exponent == 1)
out << "x" << " + ";
if(exponent == 0)
out << p.polyPtr[i];
}
}
return out;
};
//Assigns a value for exponent
void Polynomial::assignExponent()
{
for(int i = 0; i<SIZE; i++)
{
exponents[i] = (SIZE - 1) - i;
}
};
//OVERLOAD OF + OPERATOR
Polynomial Polynomial::operator+(const Polynomial& other)
{
Polynomial sum(SIZE);
int difference;
//If the first polynomial is larger
if (SIZE > other.SIZE)
{
difference = SIZE - other.SIZE;
for(int i = 0; i<SIZE; i++)
{
if(i - difference < 0)
sum.polyPtr[i] = polyPtr[i];
else
{
sum.polyPtr[i] = polyPtr[i] +
other.polyPtr[i - difference];
}
}
}
//If the second polynomial is larger **PROBLEM**
if(other.SIZE > SIZE)
{
difference = other.SIZE - SIZE;
for(int i = 0; i<other.SIZE; i++)
{
if(i - difference < 0)
sum.polyPtr[i] = other.polyPtr[i];
else
{
sum.polyPtr[i] = other.polyPtr[i] +
polyPtr[i - difference];
}
}
}
//If the polynomials are equal
if(SIZE == other.SIZE)
{
for(int i = SIZE-1; i >= 0; i--)
{
sum.polyPtr[i] = polyPtr[i] + other.polyPtr[i];
}
}
return sum;
};
int main()
{
int polySize;
//User enters a size for the first & second polynomial
cout << "Enter a size for the first polynomial: ";
cin >> polySize;
Polynomial pOne(polySize);
cout << "\nEnter a size for the second polynomial: ";
cin >> polySize;
Polynomial pTwo(polySize);
//User enters in values (Overload of >> operator
cout << "\n\nEnter in values for the first polynomial, "
<< "in the format - (x x x x): " << endl;
cin >> pOne;
cout << "\nEnter in values for the second polynomial, "
<< "in the format - (x x x x): " << endl;
cin >> pTwo;
//Overload << operator for output
cout << "\nPolynomial 1 is: " << pOne << endl
<< "Polynomial 2 is: " << pTwo << endl;
Polynomial pThree = pOne + pTwo;
cout << "\nAfter being added together, the new polynomial is: "
<< pThree << endl;
system("pause");
}
我更新了我当前的代码，因为我没有想到打开另一个问题将是最好的方式。无论如何，在试图排列我的多项式，部分成功。唯一出现的问题是当第二多项式pTwo大于第一多项式时。我已标记代码部分 PROBLEM 。先感谢。
I have updated my current code because I did not think opening another question would be the best way to go. Anyway, in trying to line up my polynomial's to be added, I've partially succeeded. The only problem that arises is when the second polynomial, pTwo, is larger than the first. I've labeled the section of code, PROBLEM. Thanks in advance.
推荐答案
我猜想 + ：
class Polynomial
{
// ...
Polynomial operator+(const Polynomial& other);
// ...
};
Polynomial Polynomial::operator+(const Polynomial& other)
{
Polynomial sum(SIZE);
for(int i = 0; i< SIZE; i++)
{
sum.polyPtr[i] = polyPtr[i] + other.polyPtr[i];
}
return sum;
}
这篇关于使用包含数组指针的类重载+运算符（C ++）的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
