实验6 模板类、文件I/O和异常处理

实验任务4：

#pragma once

#include <iostream>
#include <stdexcept>

using namespace std;

template<typename T>
class Vector {
    public:
        Vector(int n,T value=0);
        ~Vector();
        Vector(const Vector<T> &v);
        int get_size() const;
        T& at(int i) ;
        T& operator[](int i);

        template<typename T1>
        friend void output(Vector<T1> &v);

        template<typename T2>
        friend void output(const Vector<T2> &v) ;
    private:
        T *arr;
        int length;
};

template<typename T>
Vector<T>::Vector(int n,T value): length{n} {
    if(n<0)
        throw length_error("Negative");
    arr = new T[n];
    for(int i=0;i<n;i++)
    {
        arr[i]=value;
    }
}

template<typename T>
Vector<T>::~Vector(){
    delete[] arr;
}

template<typename T>
Vector<T>::Vector(const Vector<T> &v){
    length=v.length;
    arr = new T[length];
    for(int i=0;i<length;i++)
    {
        arr[i]=v.arr[i];
    }
}

template<typename T>
int Vector<T>::get_size() const{
    return length;
}

template<typename T>
T& Vector<T>::at(int i) {
    if(i>=length)
        throw overflow_error("index out of range！");
    return arr[i];
}

template<typename T>
T& Vector<T>::operator[](int i){
    return arr[i];
}

template<typename T1>
void output( Vector<T1> &v){
    for(int i=0;i<v.length;i++)
    {
        cout<<v.arr[i]<<" ";
    }
    cout<<endl;
}

template<typename T2>
void output(const Vector<T2> &v) {
    for(int i=0;i<v.length;i++)
    {
        cout<<v.arr[i]<<" ";
    }
    cout<<endl;
}
Vector.hpp
 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 }
task4.cpp

 


 实验任务5：

  1 #include <algorithm>
  2 #include <iostream>
  3 #include <iomanip>
  4 #include <string>
  5 #include <vector>
  6 #include <fstream>
  7 
  8 using std::string;
  9 using std::vector;
 10 using std::ostream;
 11 using std::istream;
 12 using std::setw;
 13 using std::setprecision;
 14 using std::setiosflags;
 15 using std::ios_base;
 16 
 17 class Score {
 18 public:
 19     Score() = default;
 20     ~Score() = default;
 21 
 22     int get_score() const { return score; }
 23     string get_major() const { return major; }
 24 
 25     friend ostream& operator<<(ostream &out, const Score &c);
 26     friend istream& operator>>(istream &in, Score &c);
 27 
 28 private:
 29     string no;          // 学号
 30     string name;        // 姓名
 31     string major;       // 专业
 32     int score;            // 分数
 33 };
 34 
 35 ostream& operator<<(ostream &out, const Score &c) {
 36     out << setiosflags(ios_base::left);
 37     out << setw(15) << c.no
 38         << setw(15) << c.name
 39         << setw(15) << c.major
 40         << setw(5) << c.score;
 41 
 42     return out;
 43 }
 44 
 45 istream& operator>>(istream &in, Score &c) {
 46     in >> c.no >> c.name >> c.major >> c.score;
 47 
 48     return in;
 49 }
 50 
 51 bool compare_by_score(const Score &c1, const Score &c2) {
 52     if(c1.get_major()<c2.get_major())
 53         return true;
 54 
 55     if(c1.get_major()==c2.get_major())
 56         return c1.get_score() > c2.get_score();
 57 
 58     return false;
 59 }
 60 
 61 // 把对象中的元素插入到输出流out
 62 void output(ostream &out, const vector<Score> &v) {
 63     for(auto &i: v)
 64         out << i << std::endl;
 65 }
 66 
 67 
 68 // 把对象中的元素写到filename文件中
 69 void save(const string &filename, vector<Score> &v) {
 70     using std::ofstream;
 71 
 72     ofstream out(filename);
 73     if(!out.is_open()) {
 74         std::cout << "fail to open file to write\n";
 75         return;
 76     }
 77 
 78     output(out, v);
 79     out.close();
 80 }
 81 
 82 // 从文件filename读取对象
 83 void load(const string &filename, vector<Score> &v) {
 84     using std::ifstream;
 85 
 86     ifstream in(filename);
 87     if(!in.is_open()) {
 88         std::cout << "fail to open file to read\n";
 89         return;
 90     }
 91 
 92     std::string title_line;
 93     getline(in, title_line);     // 跳过标题行
 94 
 95     Score t;
 96     while(in >> t)
 97         v.push_back(t);
 98 
 99     in.close();
100 }
101 
102 void test() {
103 
104     vector<Score> v;
105 
106     load("data5.txt", v);
107     sort(v.begin(), v.end(),compare_by_score);
108     output(std::cout, v);    // 输出对象v中信息到屏幕
109     save("ans5.txt", v);
110 }
111 
112 int main() {
113     test();
114 }
task5.cpp

 

 

posted @ 2024-12-18 17:31  nightlight  阅读(3)  评论(0)  编辑  收藏  举报