任务4
代码：
Vector.hpp:
1 #pragma once
2 #include<iostream>
3 #include<stdexcept>
4 #include<cmath>
5
6 using namespace std;
7
8 template<typename T>
9 class Vector {
10 public:
11 Vector(int s ) :size{ s } {
12 if (s < 0)
13 throw std::length_error("vector constructor:negative size");
14
15 ptr = new T[size];
16 }
17
18 Vector(int s , T value ) :size{ s } {
19 if (s < 0)
20 throw std::length_error("vector constructor:negative size");
21
22 ptr = new T[size];
23 for (int i = 0; i < size; ++i)
24 ptr[i] = value;
25 }
26
27 Vector(const Vector<T>& v) :size{ v.size }, ptr{ new T[size] } {
28 for (int i = 0; i < size; ++i)
29 ptr[i] = v.ptr[i];
30 }
31
32 ~Vector() { delete[]ptr; }
33
34 int get_size() { return size; }
35
36 T& at(int index)const {
37 if (index < 0 || index >= size)
38 throw std::out_of_range("vector::at():index out of this->size");
39
40 return ptr[index];
41 }
42
43 T& operator[](int index) {
44 if (index < 0 || index >= size)
45 throw std::out_of_range("vector::operator[]():index out of this->size");
46
47 return ptr[index];
48 }
49
50 friend void output(const Vector<T>v) {
51 for (int i = 0; i < v.size; i++)
52 cout << v.at(i) << ",";
53 cout << "\b\b\n";
54 }
55
56 private:
57 int size;
58 T* ptr;
59 };
task4.cpp:
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 x2.at(0) = 77;
21 x2.at(1) = 777;
22 cout << "x2:"; output(x2);
23 cout << "x3:"; output(x3);
24 }
25
26 void test2() {
27 using namespace std;
28
29 int n, index;
30 while (cout << "Enter n and index:", cin >> n >> index) {
31 try {
32 Vector<int>v(n, n);
33 v.at(index) = -999;
34 cout << "v:"; output(v);
35 }
36 catch (const exception& e) {
37 cout << e.what() << endl;
38 }
39 }
40 }
41
42 int main() {
43 std::cout << "测试1：模板类接口测试\n";
44 test1();
45
46 std::cout << "\n测试2：模板类异常处理测试\n";
47 test2();
48 }
运行结果：
任务5
代码：
1 #include<iostream>
2 #include<fstream>
3 #include<string>
4 #include<vector>
5 #include<iomanip>
6 #include<algorithm>
7
8 using namespace std;
9
10 class student{
11 public:
12 student() = default;
13 ~student() = default;
14
15 string get_major()const {
16 return major;
17 }
18
19 int get_score()const {
20 return score;
21 }
22
23 friend ostream& operator<<(ostream& out, const student& s) {
24 out << setiosflags(ios_base::left);
25 out << setw(10) << s.number
26 << setw(10) << s.name
27 << setw(10) << s.major
28 << setw(10) << s.score;
29
30 return out;
31 }
32
33 friend istream& operator>>(istream& in, student& s) {
34 in >>s.number >> s.name >> s.major >> s.score;
35
36 return in;
37 }
38
39 private:
40 string number;
41 string name;
42 string major;
43 int score;
44
45 };
46
47 bool compare(const student& s1, const student& s2) {
48 if (s1.get_major() < s2.get_major())
49 return true;
50
51 if (s1.get_major() == s2.get_major())
52 return s1.get_score() > s2.get_score();
53
54 return false;
55 }
56
57 void output(ostream& out, const vector<student>& v) {
58 for (auto& i : v)
59 out << i << endl;
60 }
61
62 void save(const string& filename, vector<student>& v) {
63 ofstream out(filename);
64 if (!out.is_open()) {
65 cout << "fail to open file to write\n";
66 return;
67 }
68
69 output(out, v);
70 out.close();
71 }
72
73 void load(const string& filename, vector<student>& v) {
74 ifstream in(filename);
75 if (!in.is_open()) {
76 cout << "fail to open to read\n";
77 return;
78 }
79
80 string title_line;
81 getline(in, title_line);
82
83 student t;
84 while (in >> t)
85 v.push_back(t);
86
87 in.close();
88 }
89
90 int main() {
91 vector<student>v;
92
93 load("data5.txt", v);
94 sort(v.begin(), v.end(), compare);
95 output(cout, v);
96 save("ans5.txt", v);
97 }
运行结果：
标签：文件,return,index,int,实验,include,ptr,模板,size From： https://www.cnblogs.com/sqmylc/p/18610664