task4
源码：
1 #include<iostream>
2 #include <stdexcept>
3 #include <algorithm>
4
5 template<typename T>
6 class Vector{
7 private:
8 T* data;
9 size_t size; //无符号整数类型
10
11 public:
12 Vector(int n=0, T value = T());//后面调用默认构造函数
13 //拷贝构造函数
14 Vector(const Vector<T>& other);
15 ~Vector();
16
17 //获取数据项个数
18 size_t get_size() const;
19
20 //at()
21 T& at(int index);
22 const T& at(int index) const;
23
24 //重载[]操作符
25 T& operator[](int index);
26 const T& operator[](int index) const;
27
28 template <typename T1>
29 friend void output(const Vector<T1>& vec);
30 };
31
32
33 template <typename T>
34 Vector<T>::Vector(int n, T value) {
35 if(n < 0) {
36 throw std::length_error("Vector constructor: negative size");
37 }
38 size = n;
39 data = new T[size];
40 //将动态数组 data 中的每个元素都初始化为 value 的值
41 std::fill(data, data+size, value);
42 }
43
44 template <typename T>
45 Vector<T>::Vector(const Vector<T>& other){
46 size = other.size;
47 data = new T[size];
48 std::copy(other.data, other.data+size, data);//深拷贝
49 }
50
51 template <typename T>
52 Vector<T>::~Vector(){
53 delete[] data;
54 }
55
56 template <typename T>
57 size_t Vector<T>::get_size() const{
58 return size;
59 }
60
61
62 //at()
63 template <typename T>
64 T& Vector<T>::at(int index){
65 if(index < 0 || index >= size) {
66 throw std::out_of_range("Vector: Index is out of range");
67 }
68 return data[index];
69 }
70
71 template <typename T>
72 const T& Vector<T>::at(int index) const {
73 if (index < 0 || index >= size) {
74 throw std::out_of_range("Index is out of range");
75 }
76 return data[index];
77 }
78
79
80 // 重载 [] 操作符
81 template <typename T>
82 T& Vector<T>::operator[](int index) {
83 if (index < 0 || index >= size) {
84 throw std::out_of_range("Index is out of range");
85 }
86 return data[index];
87 }
88
89 // const 重载 [] 操作符
90 template <typename T>
91 const T& Vector<T>::operator[](int index) const {
92 if (index < 0 || index >= size) {
93 throw std::out_of_range("Index is out of range");
94 }
95 return data[index];
96 }
97
98 template <typename T>
99 void output(const Vector<T>& vec) {
100 for (size_t i = 0; i < vec.size; ++i) {
101 std::cout << vec.data[i] << " ";
102 }
103 std::cout << std::endl;
104 }
Vector.hpp
1 #include <iostream>
2 #include "Vector.hpp"
3
4 using namespace std;
5
6 void test1() {
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 std::cout << "测试1：模板类接口测试\n";
48 test1();
49
50 std::cout << "\n测试2：模板类异常处理测试\n";
51 test2();
52 }
task4.cpp
运行结果：
task5
源码：
1 #include <iostream>
2 #include <fstream>
3 #include <vector>
4 #include <string>
5 #include <algorithm>
6
7 using namespace std;
8
9 class Student {
10 public:
11 string student_id;
12 string name;
13 string major;
14 int score;
15
16 Student(string id, string n, string m, int s):
17 student_id(id), name(n), major(m), score(s) {}
18
19 void print() const {
20 cout << student_id << "\t" << name << "\t" << major << "\t" << score << endl;
21 }
22 };
23
24
25 class StudentManager {
26 private:
27 vector<Student> students;
28
29 public:
30 void readData(const string& filename) {
31 ifstream infile(filename);
32 if (!infile.is_open()) {
33 cerr << "can't open the file " << filename << endl;
34 return;
35 }
36
37 //跳过标题行
38 string line;
39 getline(infile, line);
40
41 //读取数据(通过'\t'实现)
42 while (getline(infile, line)) {
43 size_t pos = 0;
44 string student_id, name, major;
45 int score;
46
47 //获取学号
48 pos = line.find('\t');
49 student_id = line.substr(0, pos);
50 line.erase(0, pos + 1);
51
52 //获取姓名
53 pos = line.find('\t');
54 name = line.substr(0, pos);
55 line.erase(0, pos + 1);
56
57 //获取专业
58 pos = line.find('\t');
59 major = line.substr(0, pos);
60 line.erase(0, pos + 1);
61
62 //获取分数
63 score = stoi(line);
64
65 //创建学生对象并添加到vector
66 students.push_back(Student(student_id, name, major, score));
67 }
68 infile.close();
69 }
70
71 void sortStudents() {
72 sort(students.begin(), students.end(),
73 [](const Student& a, const Student& b) {
74 if(a.major != b.major) {
75 return a.major < b.major;
76 }
77 return a.score > b.score;
78 });
79 }
80
81 void printToScreen() {
82 cout << "学号\t姓名\t专业\t分数" << endl;
83 for(const auto& student : students) {
84 student.print();
85 }
86 }
87
88 void writeToFile(const string& filename) {
89 ofstream outfile(filename);
90 if(!outfile.is_open()) {
91 cerr << "can't open the file " << filename << endl;
92 return;
93 }
94
95 outfile << "学号\t姓名\t专业\t分数" << endl;
96 for(const auto& student : students) {
97 outfile << student.student_id << "\t"
98 << student.name << "\t"
99 << student.major << "\t"
100 << student.score << endl;
101 }
102 outfile.close();
103 }
104 };
students.hpp
1 #include"students.hpp"
2
3 int main() {
4 StudentManager manager;
5
6 //读取数据
7 manager.readData("data5.txt");
8
9 //排序
10 manager.sortStudents();
11
12 //输出到屏幕
13 manager.printToScreen();
14
15 //写入文件
16 manager.writeToFile("ans5.txt");
17
18 return 0;
19 }
task5.cpp
运行结果：
标签：文件,const,index,int,Vector,实验,data,模板,size From： https://www.cnblogs.com/yrx0415/p/18610262