task4:
Vector.hpp:
1 #pragma once
2 #include<iostream>
3 #include<stdexcept>
4 using namespace std;
5
6 template<typename T>
7 class Vector
8 {
9 private:
10 int size;
11 T* ptr;
12 public:
13 Vector(int n);
14 Vector(int n, T value);
15 Vector(const Vector<T>& v);
16 ~Vector();
17
18 int get_size()
19 {
20 return size;
21 }
22
23 T& at(int index)const;
24 T& at(int index);
25
26 T& operator[](int index)const;
27 T& operator[](int index);
28
29 template<typename T1> //模板类中的友元函数，一定要再次声明一个T1，不然就要报错
30 friend void output(const Vector<T1>& v);
31 };
32
33 template<typename T>
34 Vector<T>::Vector(int n) :size(n)
35 {
36 if (n < 0)
37 {
38 throw length_error("Vector constructor:negative size");
39 }
40 else
41 {
42 ptr = new T[size];
43 }
44 }
45
46
47 template<typename T>
48 Vector<T>::Vector(int n,T value):size(n)
49 {
50
51 if (n < 0)
52 {
53 throw length_error("Vector constructor:negative size");
54 }
55 else
56 {
57 ptr = new T[size];
58 for (int i = 0; i < size; i++)
59 {
60 ptr[i] = value;
61
62 }
63 }
64
65
66 }
67
68 template<typename T>
69 Vector<T>::Vector(const Vector<T>& v):size(v.size),ptr(new T[size])
70 {
71 for (int i = 0; i < size; i++)
72 {
73 ptr[i] = v.ptr[i];
74 }
75
76 }
77
78 template<typename T>
79 Vector<T>::~Vector()
80 {
81
82 delete[]ptr;
83 }
84
85 template<typename T>
86 T& Vector<T>::at(int index)const
87 {
88 if (index < 0 || index >= size)
89 {
90 throw out_of_range("Vector:index out of range");
91 }
92 else
93 {
94 return ptr[index];
95 }
96
97 }
98
99 template<typename T>
100 T& Vector<T>::at(int index)
101 {
102 return static_cast<const Vector*>(this)->at(index);
103
104 }
105
106 template<typename T>
107 T& Vector<T>::operator[](int index)const
108 {
109 if (index < 0 || index >= size)
110 {
111 throw out_of_range("Vector:index out of range");
112 }
113 else
114 {
115 return ptr[index];
116 }
117
118 }
119 template<typename T>
120 T& Vector<T>::operator[](int index)
121 {
122 return static_cast<const Vector*>(this)->operator[](index);
123
124 }
125
126 template<typename T>
127 void output(const Vector<T>& v)
128 {
129 for (int i = 0; i < v.size; i++)
130 {
131 cout << v.ptr[i] << ", ";
132 }
133 cout <<"\b\b " << endl;
134
135 }
View Code
task4:
1 #include <iostream>
2 #include "Vector.hpp"
3
4 void test1()
5 {
6 using namespace std;
7
8 int n;
9 cout << "Enter n: ";
10 cin >> n;
11
12 Vector<double> x1(n);
13 for(auto i = 0; i < n; ++i)
14 x1.at(i) = i * 0.7;
15
16 cout << "x1: "; output(x1);
17
18 Vector<int> x2(n, 42);
19 const Vector<int> x3(x2);
20
21 cout << "x2: "; output(x2);
22 cout << "x3: "; output(x3);
23
24 x2.at(0) = 77;
25 x2.at(1) = 777;
26 cout << "x2: "; output(x2);
27 cout << "x3: "; output(x3);
28 }
29
30 void test2() {
31 using namespace std;
32
33 int n, index;
34 while(cout << "Enter n and index: ", cin >> n >> index) {
35 try {
36 Vector<int> v(n, n);
37 v.at(index) = -999;
38 cout << "v: "; output(v);
39 }
40 catch (const exception &e) {
41 cout << e.what() << endl;
42 }
43 }
44 }
45
46 int main() {
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 }
View Code
task5:
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 }
View Code
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 }
View Code
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 }
View Code
实验总结：
通过这次实验，加深了对模板类的使用，了解了部分模板类中的友元函数用模板时，还需要重新定义一个模板参数T1，等，否则就会报错，比如task4中的outpu函数，起初没有用T1，就出现了报错；还学会了报错的简单处理
也加深了对流类库的使用，再task5中，也了解到sort函数，最后一个参数只需要是函数指针即可，不是完整函数
标签：index,const,int,c++,Vector,实验,include,size From： https://www.cnblogs.com/jiangyuhui/p/18613333