C++中如何在函数模板increase内使用重载的operator+运算符

Got it, let's work through this school assignment step by step. You need to implement overloaded operators for your Inductor class and call them inside a function template named increase—here's how to complete everything properly:

First, let's finish the Inductor class implementation based on the partial code you provided. We'll fill in the constructor, operator overloads, and add helper methods to interact with the private inductance member:

#pragma once
#include <iostream>
using namespace std;

class Inductor {
    friend ostream& operator<<(ostream&, const Inductor&);
private:
    int inductance;
    double maxCurrent;
public:
    int operator+(int add);
    int operator-(int sub);
    Inductor(int, double);
    // Helper methods to access/modify private inductance
    void setInductance(int newInd);
    int getInductance() const;
};

// Constructor definition
Inductor::Inductor(int ind, double maxCurr) 
    : inductance(ind), maxCurrent(maxCurr) {}

// Overloaded + operator: returns inductance + input value
int Inductor::operator+(int add) {
    return inductance + add;
}

// Overloaded - operator: returns inductance - input value
int Inductor::operator-(int sub) {
    return inductance - sub;
}

// Friend ostream operator to print Inductor details
ostream& operator<<(ostream& os, const Inductor& inductor) {
    os << "Inductance: " << inductor.inductance << " mH, Max Current: " << inductor.maxCurrent << " A";
    return os;
}

// Setter for inductance
void Inductor::setInductance(int newInd) {
    inductance = newInd;
}

// Getter for inductance
int Inductor::getInductance() const {
    return inductance;
}

Next, let's build the increase function template. The requirement is to call the overloaded operator+ inside this template—we'll use it to calculate the new inductance value and update the object:

template <typename T>
void increase(T& obj, int increment) {
    // Call the overloaded + operator to compute the new inductance
    int updatedInductance = obj + increment;
    // Update the object's inductance using the setter
    obj.setInductance(updatedInductance);
    // Optional: Print the result to verify the change
    cout << "After increase: " << obj << endl;
}

Example Test Code #

To see this in action, add a main function to test the implementation:

int main() {
    // Create an Inductor instance: 80mH, max current 3.0A
    Inductor coil(80, 3.0);
    cout << "Original state: " << coil << endl;

    // Use the increase template to add 40mH
    increase(coil, 40);

    // Add another 25mH
    increase(coil, 25);

    return 0;
}

Quick Explanations #

• We added getInductance and setInductance because the inductance member is private—this lets us safely update the object's state after using the overloaded operator+.
• The increase template is generic, so it could work with any class that has an overloaded operator+ accepting an int and a way to update its internal value (like the setInductance method here).
• The overloaded operators follow your class declaration exactly—returning an int as specified.

内容的提问来源于stack exchange，提问作者Sarah Collins