实验二 函数重载、函数模板、简单类的定义和实现

一、实验内容

1、函数重载编程练习

编写重载函数add()，实现对int型，double型，complex型数据的加法。

#include<iostream>
using namespace std;
struct Complex{
    double real;
    double imaginary;
};

int add(int x,int y){
    return x+y;
}
double add(double x,double y){
    return x+y;
}
Complex add(Complex x,Complex y){
    Complex z;
    z.imaginary=x.imaginary+y.imaginary;
    z.real=x.real+y.real; 
    return z;
}

int main(){
    int a,b;
    cout<<"Enter two integer:";
    cin>>a>>b;
    cout<<"The answer is:"<<add(a,b)<<endl;
    
    double m,n;
    cout<<"Enter two real number:";
    cin>>m>>n;
    cout<<"The answer is:"<<add(m,n)<<endl;
    
    struct Complex p,q;
    cout<<"Enter two struct:";
    cin>>p.real>>p.imaginary>>q.real>>q.imaginary;
    cout<<"The answer is:"<<add(p,q).real<<"+"<<add(p,q).imaginary<<"i"<<endl;
    
    return 0;
}

结果如下：

2、函数模板编程练习

编写实现快速排序函数模板，并在main函数中，定义不同类型数据，调用测试。

//quicksort.h
# ifndef QS_H 
# define QS_H

template<class T>
void QuickSort(T a[], int low, int high) {
    int i = low, j = high - 1, p;
    T k = a[i];
    if (i < j) {
        while (i < j) {
            while ((a[j] >= k) && i < j) j--;
            a[i] = a[j];
            while ((a[i] <= k) && i < j) i++;
            a[j] = a[i];
        }
        a[i] = k;
    }
    else  return;
    QuickSort(a, low, i);
    QuickSort(a, i + 1, high);
} 
# endif

//output.h
# ifndef OP_H
# define OP_H
# include<iostream>
using namespace std;

template<class T>
void output(T a[], int n) {
    for (int i = 0;i < n;i++)
        cout << a[i] << " ";
    cout << endl;
}

# endif

//MAIN.cpp
#include<iostream>
#include<string>
#include"output.h"
#include"quicksort.h"
#define M 8
#define N 10
using namespace std;

int main() {
    int a[N] = { 8,4,2,34,76,36,13,89,32,64 };
    double b[M] = { 7.1,3.4,2.3,7.8,3.2,3.4,8.7,5.6 };
    cout << "the array is:" << endl;
    output(a, N);
    output(b, M);

    cout << "after sorting:" << endl;
    int m = 0;
    QuickSort(a, m, N);
    QuickSort(b, m, M);
    output(a, N);
    output(b, M);
 
    system("pause");
    return 0;
}

效果如下：

 3、类的定义、实现和使用编程练习。

#include<iostream>
#include<string>
using namespace std;

//User类声明
class User {
public:
    void setInfo(string name0,string passwd0 = "111111", string email0 = " ");//支持设置用户信息
    void changePasswd();                                       //支持修改密码
    void printInfo();                                          //支持打印用户信息
    void changemail();                                         //支持修改邮箱
private:
    string name;
    string passwd;
    string email;
};
void User::setInfo(string name0, string passwd0, string email0) {
    name = name0;
    passwd = passwd0;
    email = email0;
}

void User::changePasswd() {
    string passwd1, passwdN;
    int n=1;
    cout << "Enter the old passwd:";
    cin >> passwd1;
    while (n <= 3) {
        if (User::passwd == passwd1) {
            cout << "Enter the new passwd:";
            cin >> passwdN;
            break;
        }
        else if(n<3&&(User::passwd != passwd1)) {
            cout << "passwd input error,Please re-Enter again:";
            cin >> passwd1;
            n++;
        }
        else if (n == 3 && (User::passwd != passwd1)) {
            cout << "Please try after a while." << endl;
            break;
        }
    }
}

void User::printInfo() {
    cout << "name:		" << name << endl;
    cout << "passwd:		" <<"******"<< endl;
    cout << "email:		" << email << endl;
}

void User::changemail() {
    string emailN;
    char a = '@';
    string::size_type idx;        //string类提供字符串中查找另一字符串的函数find
    cout << "Enter the new email:";
    cin >> emailN;
    idx = emailN.find(a);         //在emailN中查找a
    while (idx == string::npos) { //不存在
        cout << "Add @ to your email:";
        cin >> emailN;
        idx = emailN.find(a);
    }

}

int main() {
    cout << "testing 1......" << endl << endl;

    User user1;
    user1.setInfo("Leonard");
    user1.printInfo();
    user1.changePasswd();
    user1.printInfo();

    cout << endl << "testing 2......" << endl << endl;
    User user2;
    user2.setInfo("Jonny", "92197", "xyz@hotmail.com");
    user2.printInfo();
    user2.changemail();

    system("pause");
    return 0;
}

结果如下：

二、实验反思

1、快速排序实验写了很久，也拿不同数据测了多次，有时一串数可以换些有特点的数就不行了。上网查了下，语句位置不一样，条件内容不一样，就会出现问题。写代码还是需要严谨，不可以拿自己思维与计算机比较。

2、类的实验看似复杂冗长，其实静下心来就可以顺利写下来，一直困在实验二又不敢着手于实验三。后来学到c++中的查找字符串还是比较兴奋的。

3、花了很多时间在这次实验上，不仅仅因为快速排序，更多是小细节上出错，以后会多多练习。

三、实验评论

https://www.cnblogs.com/Kun-520/p/10589170.html#4212874

https://www.cnblogs.com/xtn-0326/p/10587619.html#4212940

https://www.cnblogs.com/jessi-wu1005/p/10588322.html#4212849