实验6 模板类、文件I/O和异常处理

实验任务4

 1 #ifndef VECTOR_HPP
 2 #define VECTOR_HPP
 3 
 4 #include <iostream>
 5 #include <stdexcept>
 6 
 7 template<typename T>
 8 class Vector {
 9 private:
10     T* data;
11     size_t size;
12 
13 public:
14     // 构造函数，动态指定大小
15     Vector(size_t n) {
16         if (n < 0) {
17             std::cerr << "Vector constructor: negative size" << std::endl;
18         }
19         size = n;
20         data = new T[size];
21     }
22 
23     // 构造函数，动态指定大小并初始化每个数据项
24     Vector(size_t n, const T& value) {
25         if (n < 0) {
26             std::cerr << "Vector constructor: negative size" << std::endl;
27         }
28         size = n;
29         data = new T[size];
30         for (size_t i = 0; i < size; ++i) {
31             data[i] = value;
32         }
33     }
34 
35     // 深拷贝构造函数
36     Vector(const Vector& other) {
37         size = other.size;
38         data = new T[size];
39         for (size_t i = 0; i < size; ++i) {
40             data[i] = other.data[i];
41         }
42     }
43 
44     // 析构函数
45     ~Vector() {
46         delete[] data;
47     }
48 
49     // 返回动态数组对象中数据项个数
50     size_t get_size() const {
51         return size;
52     }
53 
54     // at() 方法，支持下标访问并处理越界异常
55     T& at(size_t i) {
56         if (i >= size) {
57             throw std::out_of_range("Index out of range");
58         }
59         return data[i];
60     }
61 
62     const T& at(size_t i) const {
63         if (i >= size) {
64             throw std::out_of_range("Index out of range");
65         }
66         return data[i];
67     }
68 
69     // 重载 [] 运算符
70     T& operator[](size_t i) {
71         return at(i);
72     }
73 
74     const T& operator[](size_t i) const {
75         return at(i);
76     }
77 
78     // 友元函数，用于输出 Vector 对象中的数据项
79     friend void output(const Vector& vec) {
80         for (size_t i = 0; i < vec.size; ++i) {
81             std::cout << vec.data[i] << " ";
82         }
83         std::cout << std::endl;
84     }
85 };
86 
87 #endif // VECTOR_HPP

 1 #include <iostream>
 2 #include "Vector.hpp"
 3 
 4 void test1() {
 5     using namespace std;
 6 
 7     int n;
 8     cout << "Enter n: ";
 9     cin >> n;
10     
11     Vector<double> x1(n);
12     for(auto i = 0; i < n; ++i)
13         x1.at(i) = i * 0.7;
14 
15     cout << "x1: "; output(x1);
16 
17     Vector<int> x2(n, 42);
18     const Vector<int> x3(x2);
19 
20     cout << "x2: "; output(x2);
21     cout << "x3: "; output(x3);
22 
23     x2.at(0) = 77;
24     x2.at(1) = 777;
25     cout << "x2: "; output(x2);
26     cout << "x3: "; output(x3);
27 }
28 
29 void test2() {
30     using namespace std;
31 
32     int n, index;
33     while(cout << "Enter n and index: ", cin >> n >> index) {
34         try {
35             Vector<int> v(n, n);
36             v.at(index) = -999;
37             cout << "v: "; output(v);
38         }
39         catch (const exception &e) {
40             cout << e.what() << endl;
41         }
42     }
43 }
44 
45 int main() {
46     using namespace std;
47     cout << "测试1: 模板类接口测试\n";
48     test1();
49 
50     cout << "\n测试2: 模板类异常处理测试\n";
51     test2();
52 }

运行测试截图

实验任务5

 1 #include <iostream>
 2 #include <fstream>
 3 #include <sstream>
 4 #include <vector>
 5 #include <algorithm>
 6 #include <string>
 7 
 8 // 定义学生结构体
 9 struct Student {
10     std::string id;
11     std::string name;
12     std::string major;
13     int score;
14 };
15 
16 // 比较函数，用于按专业字典序和分数降序排序
17 bool compareStudents(const Student& a, const Student& b) {
18     if (a.major != b.major) {
19         return a.major < b.major; // 先按专业字典序排序
20     } else {
21         return a.score > b.score; // 专业相同时，按分数降序排序
22     }
23 }
24 
25 // 从文件中读取学生数据
26 std::vector<Student> readStudentsFromFile(const std::string& filename) {
27     std::vector<Student> students;
28     std::ifstream file(filename);
29     std::string line;
30 
31     // 跳过标题行
32     if (std::getline(file, line)) {
33         while (std::getline(file, line)) {
34             std::istringstream iss(line);
35             Student student;
36             std::getline(iss, student.id, '\t');
37             std::getline(iss, student.name, '\t');
38             std::getline(iss, student.major, '\t');
39             std::getline(iss, line, '\t'); // 读取分数前的制表符和分数后的换行符或空格等
40             std::stringstream ss(line);
41             ss >> student.score;
42             students.push_back(student);
43         }
44     }
45 
46     file.close();
47     return students;
48 }
49 
50 // 将学生数据写入文件
51 void writeStudentsToFile(const std::vector<Student>& students, const std::string& filename) {
52     std::ofstream file(filename);
53     file << "学号\t姓名\t专业\t分数" << std::endl;
54     for (const auto& student : students) {
55         file << student.id << "\t" << student.name << "\t" << student.major << "\t" << student.score << std::endl;
56     }
57     file.close();
58 }
59 
60 // 打印学生数据到屏幕
61 void printStudentsToScreen(const std::vector<Student>& students) {
62     for (const auto& student : students) {
63         std::cout << student.id << "\t" << student.name << "\t" << student.major << "\t" << student.score << std::endl;
64     }
65 }
66 
67 int main() {
68     std::vector<Student> students = readStudentsFromFile("data5.txt");
69 
70     // 对学生数据进行排序
71     std::sort(students.begin(), students.end(), compareStudents);
72 
73     // 打印排序后的学生数据到屏幕
74     printStudentsToScreen(students);
75 
76     // 将排序后的学生数据写入文件
77     writeStudentsToFile(students, "ans5.txt");
78 
79     return 0;
80 }

运行测试截图