cpp 实验6

vector.h
#pragma once
#include<iostream>
#include<stdexcept>
using namespace std;
template<typename T>
class Vector {
private:
    int size;
    T* ptr;
public:
    Vector(int size, T value =T() ) :size{ size } {
        if (size < 0) {
            throw length_error("negative size");
        }
        ptr = new T[size];
        for (int i = 0; i < size; i++) {
            ptr[i] = value;
        }
    }
    int get_size()const { return size; }
    T& at(int index)const {
        if (index < 0 || index >= size) throw out_of_range("index out of range");
        return ptr[index];
    }
    T& at(int index) {
        return static_cast<const Vector<T>*>(this)->at(index);
    }
    T& operator[](int index)const {
        if (index < 0 || index >= size) throw out_of_range("index out of range");
        return ptr[index];
    }
    T& operator[](int index) {
        return static_cast<const Vector<T>*>(this)->operator[](index);
    }
};
template<typename T1>
void output(const Vector<T1>& v) {
    for (int i = 0; i < v.get_size();i++) {
        cout << v[i]<<", ";
    }
    cout << endl;
}




task4 cpp
#include <iostream>
#include "Vector.h"
void test1() {
    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();
}

 

#include<iostream>
#include<fstream>
#include<algorithm>
#include<vector>
#include<iomanip>
using namespace std;
struct stu
{
    string no;
    string name;
    string major;
    int score;
    stu(string no,string name,string major,int score):no{no},name{name},major{major},score{score}{}
};
bool compare(stu x, stu y) {
    if(x.major!=y.major)
        return x.major < y.major;
    else{
        return x.score > y.score;
    }
}
int main() {
    ifstream input("data5.txt");
    if (!input.is_open()) {
        cout << "无法加载文件中的数据" << endl;
        return 0;
    }
    string no, name, major;
    int score;
    vector<stu> v;
    while (input >> no >> name >> major >> score) {
        v.push_back(stu(no, name, major, score));
    }
    input.close();
    sort(v.begin(), v.end(), compare);
    ofstream output("ans5.txt");
    if (!output.is_open()) {
        cout << "文件加载失败" << endl;
    }
    for (auto i : v) {
        cout << setiosflags(ios_base::left);
        cout << setw(10) << i.no << setw(10) << i.name << setw(10) << i.major << setw(10) << i.score << endl;
        output << i.no << "  " << i.name << "  " << i.major << "  " << i.score << endl;
    }
    output.close();
    return 0;
}