EX3 ANSWER

```cmakelists.txt
cmake_minimum_required(VERSION 3.15)

project(GradeManager VERSION 1.0)

# 定义源文件列表
set(SOURCES
    src/student.cpp
    src/grade.cpp
    src/report.cpp
)

# 创建可执行文件
add_executable(grademanager 
    main.cpp
    ${SOURCES}
)

# 设置包含目录
target_include_directories(grademanager PRIVATE include/)

# 设置 C++ 标准
set_property(TARGET grademanager PROPERTY CXX_STANDARD 17)
set_property(TARGET grademanager PROPERTY CXX_STANDARD_REQUIRED ON)

```

```main.cpp
#include <iostream>
#include <vector>
#include <string>
#include "student.h"
#include "grade.h"
#include "report.h"

int main() {
    std::cout << "Student Grade Manager" << std::endl;
    std::cout << "=====================\n" << std::endl;
    
    // Get student information
    std::string name;
    int id;
    
    std::cout << "Enter student name: ";
    std::getline(std::cin, name);
    
    std::cout << "Enter student ID: ";
    std::cin >> id;
    
    Student student(name, id);
    
    // Get grades
    std::vector<double> grades;
    double grade;
    
    std::cout << "\nEnter grades (enter -1 to finish):" << std::endl;
    
    int count = 1;
    while (true) {
        std::cout << "Grade " << count << ": ";
        std::cin >> grade;
        
        if (grade == -1) {
            break;
        }
        
        if (grade < 0 || grade > 100) {
            std::cout << "Invalid grade. Please enter a value between 0 and 100." << std::endl;
            continue;
        }
        
        grades.push_back(grade);
        count++;
    }
    
    // Print report
    printReport(student, grades);
    
    return 0;
}

```

```src/grade.cpp
#include "grade.h"

double calculateAverage(const std::vector<double>& grades) {
    if (grades.empty()) {
        return 0.0;
    }
    
    double sum = 0.0;
    for (double grade : grades) {
        sum += grade;
    }
    
    return sum / grades.size();
}

bool isPassing(double average) {
    return average >= 60.0;
}

char getLetterGrade(double average) {
    if (average >= 90.0) return 'A';
    if (average >= 80.0) return 'B';
    if (average >= 70.0) return 'C';
    if (average >= 60.0) return 'D';
    return 'F';
}

```report.cpp
#include "report.h"
#include "grade.h"
#include <iostream>
#include <iomanip>

void printReport(const Student& student, const std::vector<double>& grades) {
    std::cout << "\nStudent Report" << std::endl;
    std::cout << "==============" << std::endl;
    
    std::cout << "Name: " << student.getName() << std::endl;
    std::cout << "ID: " << student.getId() << std::endl;
    std::cout << "Number of grades: " << grades.size() << std::endl;
    
    if (grades.empty()) {
        std::cout << "No grades entered." << std::endl;
        return;
    }
    
    double average = calculateAverage(grades);
    
    std::cout << std::fixed << std::setprecision(2);
    std::cout << "Average: " << average << std::endl;
    std::cout << "Status: " << (isPassing(average) ? "PASS" : "FAIL") << std::endl;
    std::cout << "Letter Grade: " << getLetterGrade(average) << std::endl;
}

```student.cpp
#include "student.h"

Student::Student(const std::string& name, int id) 
    : name(name), id(id) {
}

std::string Student::getName() const {
    return name;
}

int Student::getId() const {
    return id;
}

```
```include/grade.h
#pragma once
#include <vector>

/**
 * Calculate the average of a list of grades
 */
double calculateAverage(const std::vector<double>& grades);

/**
 * Check if the average grade is passing (>= 60)
 */
bool isPassing(double average);

/**
 * Get letter grade based on average
 * A: 90+, B: 80-89, C: 70-79, D: 60-69, F: <60
 */
char getLetterGrade(double average);

```
```report.h
#pragma once
#include <string>
#include <vector>
#include "student.h"

/**
 * Print a formatted grade report for a student
 */
void printReport(const Student& student, const std::vector<double>& grades);

```
```student.h
#pragma once
#include <string>

class Student {
private:
    std::string name;
    int id;

public:
    Student(const std::string& name, int id);
    
    std::string getName() const;
    int getId() const;
};

```