我试图重载加法运算符以添加两个多项式。我的想法是将多项式设为两个数组,一个用于系数,一个用于指数。添加两个多项式只是将两个数组合并为一个更长的数组。我刚刚学会了指针和&符号,但还不知道如何有效地使用它们。我得到的错误是"表达式必须是可修改的左值"。
getter和setter函数将用于组合相同指数的术语,我还没有写出来。
#include <iostream>
#include "Polynomial.h"
using namespace std;
Polynomial::Polynomial(){
};
Polynomial Polynomial::operator + (const Polynomial &right) const
{
Polynomial Sum;
Sum.numberOfTerms = numberOfTerms + right.numberOfTerms;
int i = static_cast<int>(numberOfTerms);
int j = static_cast<int>(right.numberOfTerms);
for (int n = 0; n > i && n <= n + j; n++) {
coefficients[n] = right.coefficients[n]; //error saying expression must be a modifiable lvalue
exponents[n] = right.exponents[n];
}
return Sum;
}
void Polynomial::enterTerms() {
int coefficient=0;
int exponent=0;
cout << "Enter number of terms for the polynomial:";
cin >> numberOfTerms;
for (int i = 0; i < numberOfTerms; i++) {
cout << "Enter coefficient:\n";
cin >>coefficient;
coefficients[i] = coefficient;
cout << "Enter exponent:\n";
cin >> exponent;
exponents[i] = exponent;
}
}
void Polynomial::printPolynomial() const {
//Print the first term out, if exponent is 0, just print out the constant
if (exponents[0] == 0) {
cout << coefficients[0];
}
else{
cout << coefficients[0] << "x^" << exponents[0];
}
//Print from the second term to the last term, including a "+" in front of each term
for (int i = 1; i <= numberOfTerms; i++) {
if (exponents[i] == 0) {
cout <<"+"<< coefficients[i];
}
else {
cout << "+"<<coefficients[i] << "x^" << exponents[i];
}
}
}
int Polynomial::getNumberOfTerms() const {
return numberOfTerms;
}
int Polynomial::getTermCoefficient(int i) const {
return coefficients[i];
}
int Polynomial::getTermExponent(int i) const {
return exponents[i];
}
这是头文件
#ifndef POLYNOMIAL_H
#define POLYNOMIAL_H
#include <array>
using namespace std;
class Polynomial {
public:
static const int maxTerms = 100;
Polynomial();
Polynomial operator+(const Polynomial &)const;
void enterTerms();
void printPolynomial() const;
int getNumberOfTerms() const;
int getTermExponent(int) const;
int getTermCoefficient(int) const;
void setCoefficient(int, int);
//~Polynomial();
private:
size_t numberOfTerms;
array<int, maxTerms> exponents;
array<int, maxTerms> coefficients;
static void polynomialCombine(Polynomial &);
};
#endif
答案 0 :(得分:0)
您已将运算符+声明为const:
Polynomial Polynomial::operator + (const Polynomial &right) const
^^^^^
这意味着这个 - &gt;系数[*]无法修改。即你已经创建了一个Sum对象,但是试图写入* this而不是你要返回的Sum对象。