实验6 模板类、文件I/O和异常处理

实验任务4：

Vector.hpp源码：

 1 #pragma once
 2 #include <iostream>
 3 #include <stdexcept>
 4 using namespace std;
 5 
 6 template <typename T>
 7 class Vector {
 8 public:
 9     Vector(int n) :size(n)
10     {
11         if (n < 0)
12             throw length_error("Vector constructor: negtive size");
13         pointer = new T[size];
14     }
15     Vector(int n, const T& value) :size(n)
16     {
17         if (n < 0)
18             throw length_error("Vector constructor: negtive size");
19         pointer = new T[size];
20         for (int i = 0; i < size; i++)
21             pointer[i] = value;
22     }
23     Vector(const Vector<T>& other) :size(other.size), pointer(new T[size])
24     {
25         for (int i = 0; i < size; i++)
26             pointer[i] = other.pointer[i];
27     }
28     ~Vector() = default;
29 
30     int get_size() const { return size; }
31     T& at(int index) const
32     {
33         if (index < 0 || index >= size)
34             throw out_of_range("vector:index out of range");
35         return pointer[index];
36     }
37     T& operator[](int index) const
38     {
39         if (index < 0 || index >= size)
40             throw out_of_range("vector:index out of range");
41         return pointer[index];
42     }
43 
44     friend void output(const Vector<T>& vec)
45     {
46         for (int i = 0; i < vec.get_size(); i++)
47             cout << vec.at(i) << ",";
48         cout << "\b\b\n";
49     }
50 private:
51     int size;
52     T* pointer;
53 };

task4.cpp源码：

 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     cout << "测试1: 模板类接口测试\n";
47     test1();
48 
49     cout << "\n测试2: 模板类异常处理测试\n";
50     test2();
51 }

运行结果：

实验任务5：

task5.cpp源码：

 1 #include <iostream>
 2 #include <fstream>
 3 #include <vector>
 4 #include <algorithm>
 5 #include <iomanip>
 6 #include <string>
 7 
 8 using namespace std;
 9 
10 //定义学生类
11 class student {
12     string id;
13     string name;
14     string major;
15     int score;
16 public:
17     student(string id, string name, string major, int score) : id(id), name(name), major(major), score(score) {}
18     ~student()=default;
19 
20     string get_id() {return id;}
21     string get_name() {return name;}
22     string get_major() {return major;}
23     int get_score() {return score;}
24 };
25 //排序
26 bool compare(student a, student b) {
27     if(a.get_major() < b.get_major())
28         return true;
29     else if(a.get_major() == b.get_major())
30         return a.get_score() > b.get_score();
31     return false;
32 
33 }
34 int main() {
35     //读入数据到file
36     ifstream file("data5.txt");
37     if (!file.is_open())
38     {
39         cout << "Failed to open file." << endl;
40         return 0;
41     }
42     //跳过标题
43     string line;
44     getline(file, line);
45     //读入数据到stu
46     string id, name, major;
47     int score;
48     vector<student> stu;
49     while (file >> id >> name >> major >> score)
50     {
51         student s(id, name, major, score);
52         stu.push_back(s);
53     }
54     //关掉文件
55     file.close();
56     //排序
57     sort(stu.begin(), stu.end(), compare);
58     //输出到文件result5.txt
59     ofstream out("result5.txt");
60     if (!out.is_open())
61     {
62         cout << "Failed to open output file." << endl;
63         return 0;
64     }
65     //在控制台输出结果并输出到文件
66     for (auto s : stu)
67     {
68         cout << left << setw(10) << s.get_id() << setw(10) << s.get_name() << setw(10) << s.get_major() << setw(10) << s.get_score() << endl;
69         out << left << setw(10) << s.get_id() << setw(10) << s.get_name() << setw(10) << s.get_major() << setw(10) << s.get_score() << endl;
70     }
71     //关掉文件
72     out.close();
73 
74     return 0;
75 }

运行结果：