实验6 模版类、文件I/O和异常处理

任务4：

Vector.hpp:

 1 #pragma once
 2 #include <iostream>
 3 using namespace std;
 4 
 5 template <typename T>
 6 class Vector {
 7 private:
 8     int size_;
 9     T* data_;
10 
11 public:
12 
13     Vector(int n);
14 
15     Vector(int n, T value);
16 
17     Vector(const Vector<T>& v) : size_(v.size_), data_(new T[v.size_]) {
18         for (int i = 0; i < size_; ++i) {
19             data_[i] = v.data_[i];
20         }
21     }
22 
23     ~Vector() {}
24 
25     int size() const { return size_; }
26 
27     T& at(int index) {
28         if (index < 0 || index >= size_) {
29             throw out_of_range("Vector: Index out of range");
30         }
31         return data_[index];
32     }
33 
34     const T& at(int index) const {
35         if (index < 0 || index >= size_) {
36             throw out_of_range("Vector: Index out of range");
37         }
38         return data_[index];
39     }
40 
41     T& operator[](int index) { return data_[index]; }
42     const T& operator[](int index) const { return data_[index]; }
43 
44     template <typename T1>
45     friend void output(const Vector<T1>& v);
46 };
47 
48 
49 template <typename T>
50 void output(const Vector<T>& v) {
51     for (int i = 0; i < v.size_; ++i) {
52         cout << v.data_[i];
53         if (i != v.size_ - 1) cout << ", ";
54     }
55     cout << endl;
56 }
57 template<typename T>
58 Vector<T>::Vector(int n) : size_(n){
59         if (n < 0) {
60             throw length_error("Vector constructor: negative size");
61         }
62         else
63         {
64             data_ = new T[size_];
65         }
66     }
67 template<typename T>
68 Vector<T>::Vector(int n, T value) : size_(n) {
69         if (n < 0) {
70             throw length_error("Vector constructor: negative size");
71         }
72         else
73         {
74             data_ = new T[size_];
75             for (int i = 0; i < size_; i++)
76             {
77                 data_[i] = value;
78 
79             }
80         }
81     }

task.cpp:

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

任务5：

people.hpp:

 1 #pragma once
 2 #include<iostream>
 3 #include<string>
 4 #include<iomanip>
 5 
 6 using namespace std;
 7 
 8 class people
 9 {
10 private:
11     int xuehao;
12     string name;
13     string major;
14     int score;
15 public:
16     people() = default;
17     ~people() = default;
18 
19     string get_major()const
20     {
21         return major;
22     }
23     int get_score()const
24     {
25         return score;
26     }
27 
28     friend ostream& operator<<(ostream& out, people& p);
29     friend istream& operator>>(istream& in, people& p);
30 
31 
32 };
33 
34 ostream& operator<<(ostream& out, people& p)
35 {
36     out << setiosflags(ios_base::left);
37     out << setw(10) << p.xuehao
38         << setw(10) << p.name
39         << setw(10) << p.major
40         << setw(10) << p.score << endl;
41     return out;
42 
43 }
44 
45 istream& operator>>(istream& in, people& p)
46 {
47     in >> p.xuehao >> p.name >> p.major >> p.score;
48     return in;
49 
50 
51 
52 }

tools.hpp:

 1 #pragma once
 2 #include"people.hpp"
 3 #include<iostream>
 4 #include<string>
 5 #include<fstream>
 6 #include<vector>
 7 
 8 bool paixu(const people& p1, const people& p2)
 9 {
10     if (p1.get_major() < p2.get_major())
11     {
12         return true;
13     }
14     if (p1.get_major() == p2.get_major())
15     {
16         return p1.get_score() > p2.get_score();
17 
18     }
19     return false;
20 
21 }
22 
23 void output(ostream& out, vector<people>& v)
24 {
25     for (auto& i : v)
26     {
27         out << i;
28     }
29 
30 }
31 
32 void save(const string& filename, vector<people>& v)
33 {
34     ofstream out(filename);
35     if (!out.is_open())
36     {
37         cout << "文件写入失败" << endl;
38         exit(0);
39     }
40 
41     output(out, v);
42     out.close();
43 
44 }
45 
46 void load(const string& filename, vector<people>& v)
47 {
48     ifstream in(filename);
49 
50     if (!in.is_open())
51     {
52         cout << "文件读出失败" << endl;
53         exit(0);
54     }
55 
56     string firstline;
57     getline(in, firstline);
58     people p;
59     while (in >> p)
60     {
61         v.push_back(p);
62     }
63 
64     in.close();
65 }

task5.cpp:

 1 #include"people.hpp"
 2 #include"tools.hpp"
 3 #include<iostream>
 4 #include<string>
 5 #include<vector>
 6 #include<algorithm>
 7 
 8 int main()
 9 {
10 
11     vector<people> v;
12     load("data5.txt", v);
13     sort(v.begin(), v.end(), paixu);
14 
15     output(cout, v);
16     save("ans.txt", v);
17 
18 
19     return 0;
20 }

 总结：通过本次实验我体验到异常处理的基础用法，异常处理的机制和流程
；也训练了综合应用类的封装、继承、多态特性及现代C++标准库编写正确、高效、安全代码