实验6 模板类、文件I/O和异常处理

task4:

Vector.hpp源代码:

#include<iostream>

using namespace std;

template <typename T>
class Vector
{
public:
    Vector(int nn) :n{ nn } {
        if (n < 0)throw length_error("Vector: negative size");
        elem = (T*)malloc(n * sizeof(T));
        if (!elem)exit(OVERFLOW);
    }
    Vector(int nn,T val) :n{ nn } {
        if (n < 0)throw length_error("Vector: negative size");
        elem = (T*)malloc(n * sizeof(T));
        if (!elem)exit(OVERFLOW);
        for (int i=0;i<n;i++)
        {
            elem[i] = val;
        }
    }
    Vector(const Vector<T>& b){
        n = b.n;
        elem = (T*)malloc(n * sizeof(T));
        if (!elem)exit(OVERFLOW);
        for(int i=0;i<n;i++)
        {
            elem[i] = b.elem[i];
        }
    }
    ~Vector() {
        n = 0;
        free(elem);
    }
    int getsize()
    {
        return n;
    }
    T& at(int i)
    {
        if (i < 0||i>=n)throw out_of_range("Vector: index out of range");
        return elem[i];
    }
    T& operator[](int i)
    {
        if (i < 0 || i>=n)throw out_of_range("Vector: index out of range");
        return elem[i];
    }
    template <typename T1>
    friend void output(const Vector<T1> a);
private:
    T* elem;
    int n;
};
template <typename T>
void output(const Vector<T> a)
{
    for (int i=0;i<a.n;i++)
    {
        cout << a.elem[i] << " ";
    }
    cout << endl;
}

 

task4.cpp源代码:

#include <iostream>
#include "Vector.hpp"

void test1() {
    using namespace std;

    int n;
    cout << "Enter n: ";
    cin >> n;
    
    Vector<double> x1(n);
    for(auto i = 0; i < n; ++i)
        x1.at(i) = i * 0.7;

    cout << "x1: "; output(x1);

    Vector<int> x2(n, 42);
    const Vector<int> x3(x2);

    cout << "x2: "; output(x2);
    cout << "x3: "; output(x3);

    x2.at(0) = 77;
    x2.at(1) = 777;
    cout << "x2: "; output(x2);
    cout << "x3: "; output(x3);
}

void test2() {
    using namespace std;

    int n, index;
    while(cout << "Enter n and index: ", cin >> n >> index) {
        try {
            Vector<int> v(n, n);
            v.at(index) = -999;
            cout << "v: "; output(v);
        }
        catch (const exception &e) {
            cout << e.what() << endl;
        }
    }
}

int main() {
    cout << "测试1: 模板类接口测试\n";
    test1();

    cout << "\n测试2: 模板类异常处理测试\n";
    test2();
}

 

运行结果：

 

task5:

task5.cpp源码：

#include <iostream>
#include <iomanip>
#include <string>
#include<vector>
#include <fstream>
#include <algorithm>

using std::string;
using std::ostream;
using std::istream;
using std::setw;
using std::setprecision;
using std::setiosflags;
using std::ios_base;

class student {
public:
    student() = default;
    ~student() = default;
    int get_score() const { return s; }
    friend ostream& operator<<(ostream& out, const student& c);
    friend istream& operator>>(istream& in, student& c);
    friend bool cmp1(student& a, student& b);
    friend bool cmp2(student& a, student& b);
private:
    string no; // 学号
    string name; // 姓名
    string major; // 专业
    int s; // 解题数
};
ostream& operator<<(ostream& out, const student& c) {
    out << setiosflags(ios_base::left);
    out << setw(15) << c.no
        << setw(20) << c.name
        << setw(15) << c.major
        << setw(5) << c.s;
    return out;
}
istream& operator>>(istream& in, student& c) {
    in >> c.no >> c.name >> c.major >> c.s;
    return in;
}

void output(std::ostream& out, const std::vector<student>& v) {
    for (auto& i : v)
        out << i << std::endl;
}
void save(const std::string& filename, std::vector<student>& v) {
    using std::ofstream;
    ofstream out(filename);
    if (!out.is_open()) {
        std::cout << "fail to open file to write\n";
        return;
    }
    output(out, v);
    out.close();
}

void load(const std::string& filename, std::vector<student>& v) {
    using std::ifstream;
    ifstream in(filename);
    if (!in.is_open()) {
        std::cout << "fail to open file to read\n";
        return;
    }
    std::string title_line;
    getline(in, title_line); 
    student t;
    while (in >> t)
        v.push_back(t);
    in.close();
}
bool cmp1(student& a, student& b)
{
    return a.major.compare(b.major) < 0;
}
bool cmp2(student& a, student& b)
{
    return a.s > b.s;
}
void Sort(std::vector<student>& v)
{
    sort(v.begin(), v.end(), cmp2);
    sort(v.begin(), v.end(), cmp1);
}
void test() {
    using namespace std;
    vector<student> v;
    load("data5.txt", v);
    Sort(v);
    output(cout, v);
    save("ans5.txt", v); 
}
int main() {
    test();
}

date5.txt：

 

运行结果：