实验四-现代C++标准库与类模板

 1 #include <iostream>
 2 
 3 using std::cout;
 4 using std::endl;
 5 
 6 class A{
 7 public:
 8     A(int x0, int y0): x{ x0 }, y{ y0 } {}
 9     void show() const { cout << x << ", " << y << endl; }
10 private:
11     int x, y;
12 };
13 
14 class B{
15 public:
16     B(double x0, double y0): x{ x0 }, y{ y0 } {}
17     void show() const { cout << x << ", " << y << endl;}
18 private:
19     double x, y;
20 };
21 
22 void test() {
23     cout << "测试类A: " << endl;
24     A a(3, 4);
25     a.show();
26 
27     cout << "\n测试类B: " << endl;
28     B b(3.2, 5.6);
29     b.show();
30 }
31 
32 int main() {
33     test();
34 }

 1 #include <iostream>
 2 #include <string>
 3 
 4 using std::cout;
 5 using std::endl;
 6 
 7 template<typename T>
 8 class X{
 9 public:
10     X(T x0, T y0): x{x0}, y{y0} {}
11     void show() const { cout << x << ", " << y << endl;}
12 private:
13     T x, y;
14 };
15 
16 void test() {
17     cout << "测试1: 模板类抽象类型T用int实例化" << endl;
18     X<int> x1(3, 4);
19     x1.show();
20 
21     cout << "\n测试2: 模板类抽象类型T用double实例化" << endl;
22     X<double> x2(3.2, 5.6);
23     x2.show();
24 
25     cout << "\n测试3: 模板类抽象类型T用标准库中的string实例化" << endl;
26     X<std::string> x3("hello", "c plus plus");
27     x3.show();
28 }
29 
30 int main() {
31     test();
32 }

 1 #include <iostream>
 2 #include <string>
 3 #include <limits>
 4 
 5 using namespace std;
 6 
 7 int main() {
 8     
 9     const int n = 10;
10     string prompt = string(n, '*') + "Enter a string: " + string(n, '*') + '\n';
11 
12     cout << "测试1:";
13     cout << prompt;
14     string s1;
15     cin >> s1;
16     cout << "s1: " << s1 << endl;
17     cin.ignore(numeric_limits<streamsize>::max(), '\n');
18 
19     cout << "\n测试2:";
20     cout << prompt;
21     getline(cin, s1); 
22     cout << "s1: " << s1 << endl;
23 
24     cout << "\n测试3:";
25     string s2, s3;
26     cout << prompt;
27     getline(cin, s2, ' ');
28     getline(cin, s3);
29     cout << "s2: " << s2 << endl;
30     cout << "s3: " << s3 << endl;
31 }

 1 #include <iostream>
 2 #include <string>
 3 
 4 int main() {
 5     using namespace std;
 6 
 7     string s;
 8 
 9     cout << "Enter words: \n";
10 
11     while( getline(cin, s) ) {
12         for(auto &ch: s)
13             ch = toupper(ch);
14         cout << s << "\n";
15     }
16 }

#include <iostream>
#include <string>
#include <algorithm>

int main() {
    using namespace std;

    string s1;

    cout << "Enter words: \n";
    getline(cin, s1);
    cout << "original words: \n";
    cout << s1 <<endl;
    cout << "to uppercase: \n";
    transform(s1.begin(), s1.end(), s1.begin(), ::toupper);
    cout << s1 << endl;
}

#include <iostream>
#include <string>

int main() {
    using namespace std;

    string s1, s2;
    s1 = "nuist";
    s1[0] = 'N';
    s1.at(1) = 'U';
    cout << boolalpha << (s1 == "nuist") << endl;
    cout << s1.length() << endl;
    cout << s1.size() << endl;
    s2 = s1 + ", 2050";
    cout << s2 << endl;

    string email{"xyz@gmail.com"};
    auto pos = email.find("@");
    if (pos == string::npos)
        cout << "illegal email address";
    else {
        auto s1 = email.substr(0, pos);
        auto s2 = email.substr(pos + 1);
        cout << s1 << endl;
        cout << s2 << endl;
    }

    string phone{"15216982937"};
    cout << phone.replace(3, 5, string(5, '*')) << endl;

    string s3{"cosmos"}, s4{"galaxy"};
    cout << "s3: " + s3 + " s4: " + s4 << endl;
    s3.swap(s4);
    cout << "s3: " + s3 + " s4: " + s4 << endl;

    string s5{"abc"};
    const char *pstr = s5.c_str();
    cout << pstr << endl;

    string s6{"12306"};
    int x1 = stoi(s6);
    cout << x1 << endl;

    int x2 = 12306;
    string s7 = to_string(x2);
    cout << s7 << endl;

    double x3 = 123.06;
    string s8 = to_string(x3);
    cout << s8 << endl;
}

#include <iostream>
#include <vector>


template<typename T>
void output(const T &obj) {
    for(auto &item: obj)
        std::cout << item << ", ";
    std::cout << "\b\b \n";
}

int main() {
    using namespace std;

    vector<int> v1;
    vector<int> v2(5);
    vector<int> v3(5, 42);
    vector<int> v4{1, 9, 8, 4};
    vector<int> v5{v4};

    cout << "v2: ";
    output(v2);

    cout << "v3: ";
    output(v3);

    cout << "v4: ";
    output(v4);

    cout << "v5: ";
    output(v5);
}

#include <iostream>
#include <vector>

using std::cout;
using std::endl;
using std::vector;

void output(const vector<int> &v) {
    cout << "v.size() = " << v.size() << endl;
    cout << "v.capacity() = " << v.capacity() << endl;
    cout << endl;
}

int main() {
    vector<int> v{42};
    output(v);

    v.push_back(55);
    v.push_back(90);
    output(v);

    for(auto i = 0; i < 8; ++i)
        v.push_back(i);
    output(v);

    v.pop_back();
    output(v);
}

 1 #include <iostream>
 2 #include <vector>
 3 #include <array>
 4 #include <string>
 5 #include <algorithm>
 6 
 7 using namespace std;
 8 
 9 template<typename T>
10 void output1(const T &obj) {
11     for(auto i = 0; i < obj.size(); ++i)
12         cout << obj.at(i) << ", ";
13     cout << "\b\b \n";
14 }
15 
16 template<typename T>
17 void output2(const T &obj) {
18     for(auto p = obj.cbegin(); p != obj.cend(); ++p)
19         cout << *p << ", ";
20     cout << "\b\b \n";
21 }
22 
23 template<typename T>
24 void output3(const T &obj) {
25     for(auto &item: obj) 
26         cout << item << ", ";
27     cout << "\b\b \n";
28 }
29 
30 void test1() {
31     string s1{"cplus"};
32 
33     output1(s1);
34 
35     reverse(s1.begin(), s1.end());
36     output2(s1);
37 
38     sort(s1.begin(), s1.end()); 
39     output3(s1);
40 }
41 
42 void test2() {
43     array< array<int, 4>, 3> x{1, 9, 8, 4, 2, 0, 2, 3, 2, 0, 4, 9 };
44 
45     output1( x.at(0) );
46     output2( x.at(1) );
47     output3( x.at(2) );
48 }
49 
50 void test3() {
51     vector<string> v1 {"Sheldon", "Leonard", "Howard", "Raj"};
52 
53     v1.push_back("Penny");
54     v1.push_back("Amy");
55 
56     output1(v1);
57 
58     sort(v1.begin(), v1.end(), std::greater<string>());
59     output2(v1);
60 
61     reverse(v1.begin(), v1.end());
62     output3(v1);
63 }
64 
65 int main() {
66     cout << "测试1: " << endl;
67     test1();
68 
69     cout << "测试2: " << endl;
70     test2();
71 
72     cout << "测试3: " << endl;
73     test3();
74 }

#pragma once

#include<iostream>
#include<string>
#include <iomanip>

using namespace std;
class Info{
public:
    Info(string nickname0, string contact0, string city0, int n0);
    ~Info()=default;

    void print() const;

private:
    string nickname,contact,city;
    int n;
};

Info::Info(string nickname0, string contact0, string city0, int n0)
{
    nickname = nickname0;
    contact = contact0;
    city = city0;
    n=n0;
}

void Info::print() const
{
    cout << "昵称:     " << nickname << endl;
    cout << "联系方式:     " << contact << endl;
    cout << "所在城市:     " << city << endl;
    cout << "预定参加人数:     " << n << endl;
}

 1 #include "Info.hpp"
 2 #include<iostream>
 3 #include<string>
 4 #include <vector>
 5 
 6 using namespace std;
 7 
 8 int main()
 9 {
10     const int capacity=100;
11     vector<Info> audience_info_list;
12     
13     cout << "录入信息：" << endl;
14     cout << endl;
15     cout << "昵称     联系方式(邮箱/手机号)     所在城市     预定参加人数     " << endl;
16     char choice;
17     int sum=0;
18     string name, contact, city;
19     int n;
20     while(cin >> name >> contact >> city >> n)
21     {
22         sum+=n;
23         
24         if(sum > capacity)
25         {
26             sum-=n;
27             cout << "对不起，只剩" << capacity-sum << "个位置" << endl;
28             cout << "1.输入u，更新（update）预定信息" << endl
29                  << "2.输入q, 退出预定" << endl
30                  <<"你的选择: ";
31             cin >> choice;
32             
33             if(choice=='u')
34             {
35                 cin >> name >> contact >> city >> n;
36                 Info a(name,contact,city,n);
37                 audience_info_list.push_back(a);
38                 sum+=n;
39             }
40             else 
41              break;
42         }
43         else audience_info_list.push_back(Info(name, contact, city, n));
44     }
45     cout << "截至目前，一共有" << sum << "位听众预定参加。预定听众信息如下：" << endl;
46     for(auto &Info:audience_info_list)
47     {
48         Info.print();
49     }
50 }