Question

我没有找任何人为我编码。但是，在调试修复代码时，这个概念正在逃避。

我知道我希望添加一些包含operator(n)的代码，其中(n)是运算符，但我不确定如何识别内容和位置。

尝试编译以下内容，我收到错误：

C2678   binary '<': no operator found which takes a left-hand operand of type 'Course'
C2678   binary '<': no operator found which takes a left-hand operand of type 'const Course'
C2678   binary '==': no operator found which takes a left-hand operand of type 'const Course'

编辑：添加.h，其中包含错误指向的代码：

vectorUtils.h（不是全部）： 第一次错误：

template <typename T>
int addInOrder (std::vector<T>& vectr, T value)
{
  // Make room for the insertion
  int toBeMoved = vectr.size() - 1;
  vectr.push_back(value);

  // Shift elements up to make room
  while (toBeMoved >= 0 && value < vectr[toBeMoved]) {
    vectr[toBeMoved+1] = vectr[toBeMoved];
    --toBeMoved;
  }
  // Insert the new value
  vectr[toBeMoved+1] = value;
  return toBeMoved+1;
}

第二＆amp;第三个错误：

template <typename T>
int seqOrderedSearch(const std::vector<T> list, T searchItem)
{
    int loc = 0;

    while (loc < list.size() && list[loc] < searchItem)
      {
       ++loc;
      }
    if (loc < list.size() && list[loc] == searchItem)
       return loc;
    else
       return -1;
}

因为'<'错误，我知道我正在寻找operator<和'=='我正在寻找operator==。但同样，我不知道如何识别位置，更不用说在course.h或course.cpp中实现了。

再次，我不希望你修复它（如果你这样做，好吧，但我宁愿学习！）。

main.cpp中的函数：

void readCourses (istream& courseFile, vector<Course>& courses) {
    while (courseFile) {
        string courseName;
        int courseMaxSize;

        if (courseFile >> courseName >> courseMaxSize) {
            Course c (courseName, courseMaxSize);
            addInOrder (courses, c);
        }
    }
}

course.h：

#ifndef COURSE_H 
#define COURSE_H 

#include <iostream>
#include <string>

struct Course {
    std::string name;
    int enrollment;
    int maxEnrollment;
    std::string* students; // array of student names

    Course (std::string courseName, int maxEnrollmentPermitted = 0);

    bool enroll (std::string studentName);

    void print (std::ostream& output) const;
};

inline
std::ostream& operator<< (std::ostream& out, const Course& c) {
    c.print(out);
    return out;
}
#endif

course.cpp：

#include "course.h"
#include "arrayUtils.h"

using namespace std;

Course::Course(std::string courseName, int maxEnrollmentPermitted)
    : name(courseName), enrollment(0), maxEnrollment(maxEnrollmentPermitted)
{
    students = new string[maxEnrollmentPermitted];
}

bool Course::enroll(std::string studentName) {
    if (enrollment < maxEnrollment) {
        addInOrder(students, enrollment, studentName);
        return true;
    }
    else {
        return false;
    }
}

void Course::print(std::ostream& output) const {
    output << name << "\n";
    for (int i = 0; i < enrollment; ++i) {
        output << "  " << students[i] << "\n";
    }
}

Answer 1

课程内容：

bool operator< (const Course&);
bool operator< (const Course&) const;
bool operator== (const Course&) const;

Inside course.cpp：

bool Course::operator< (const Course& course) {
    if (name < course.name)
        return true;
    else if (course.name < name)
        return false;

    if (enrollment < course.enrollment)
        return true;
    else if (course.enrollment < enrollment)
        return false;

    if (maxEnrollment < course.maxEnrollment)
        return true;
    else if (course.maxEnrollment < maxEnrollment)
        return false;

    if (students < course.students)
        return true;
    else if (course.students < students)
        return false;

    return false;
}

bool Course::operator< (const Course& course) const {
    if (name < course.name)
        return true;
    else if (course.name < name)
        return false;

    if (enrollment < course.enrollment)
        return true;
    else if (course.enrollment < enrollment)
        return false;

    if (maxEnrollment < course.maxEnrollment)
        return true;
    else if (course.maxEnrollment < maxEnrollment)
        return false;

    if (students < course.students)
        return true;
    else if (course.students < students)
        return false;

    return false;
}

bool Course::operator== (const Course& course) const {
    return name == course.name
        && enrollment == course.enrollment
        && maxEnrollment == course.maxEnrollment
        && students == course.students;
}

但是程序没有正确执行。仍在努力。

无法理解运算符重载

1 个答案: