实验6 模板类、文件I/O与异常处理

实验四

vector.hpp

  #pragma once#include<iostream>#include<stdexcept>using namespace std;template<typename T>class Vector {private:int size;T* ptr;public:Vector(int size, int value = 0) :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;}

test.cpp

#include <iostream>
#include "C:\Users\Administrator\Documents\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();
}

实验结果

 实验5

test.cpp

 

#include <string>
#include <vector>
#include<iomanip>
#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 People{private:string no;string name;string major;int score;public:People()=default;~People()=default;int get_score() const{return score;} string get_string() const{return major;}friend ostream& operator<<(ostream &out, const People &c);friend istream& operator>>(istream &in, People &c);
};ostream& operator<<(ostream &out, const People &c) {out << setiosflags(ios_base::left);out << setw(15) << c.no<< setw(15) << c.name<< setw(15) << c.major<< setw(15) << c.score; return out;
}istream& operator>>(istream &in, People &c) {in >> c.no >> c.name >> c.major >> c.score;return in;
}bool compare_by_order(const People &p1,const People &p2) {if(p1.get_string()<p2.get_string())return true;if(p1.get_string()==p2.get_string())return p1.get_score()>p2.get_score();return false;
}void output(std::ostream &out, const std::vector<People> &v) {for(auto &i: v)out << i << std::endl;
}void save(const std::string &filename, std::vector<People> &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<People> &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); 
People t;
while(in >> t)v.push_back(t);in.close();
}void test(){using namespace std;vector<People> v;load("data5.txt",v);sort(v.begin(),v.end(),compare_by_order);output(cout,v);save("ans5.txt",v); 
}int main(){test();
}

实验结果