一。实验结论：
1.ex3：
代码：
#include <iostream> #include <vector> #include <string> using namespace std; void output1(vector<string> &); void output2(vector<string> &); int main() { vector<string>likes, dislikes; likes.push_back("Music games"); likes.push_back("Dead by daylight"); likes.push_back("Japanese"); likes.push_back("Cue ball"); likes.push_back("Chemistry"); likes.push_back("etc."); cout << "-----I like these-----" << endl; output1(likes); dislikes.push_back("King of glory"); dislikes.push_back("Basketball"); dislikes.push_back("Eggplant"); dislikes.push_back("Soap opera"); dislikes.push_back("Ecomony"); dislikes.push_back("etc."); cout << "-----I dislike these-----" << endl; output1(dislikes); likes.swap(dislikes); cout << "-----I likes these-----" << endl; output2(likes); cout << "-----I dislikes these-----" << endl; output2(dislikes); return 0; } void output1(vector<string> &v) { int i; for(i=0;i<v.size();++i) { cout<<v[i]<<endl; } } void output2(vector<string> &v) { int i; for(vector<string>::iterator i=v.begin();i<v.end();++i) { cout<<*i<<endl; } }
运行结果：
2.习题6-17：
#include<iostream> using namespace std; int main() { int *p; //*p=9;指针指向不明 p=new int(9); cout<<"The value at p:"<<*p; return 0; }
习题6-18：
#include<iostream> using namespace std; int fn1() { int *p=new int(5); delete p;//释放内存 return *p; } int main() { int a=fn1(); cout<<"The value of a is "<<a; return 0; }
3.Matrix类的定义
#ifndef MATRIX_H #define MATRIX_H class Matrix { public: Matrix(int n); // ｹｹﾔ・ｯﾊ｣ｬｹｹﾔ・ｻｸ*nｵﾄｾﾘﾕ・ Matrix(int n, int m); // ｹｹﾔ・ｯﾊ｣ｬｹｹﾔ・ｻｸ*mｵﾄｾﾘﾕ・ Matrix(const Matrix &X); // ｸｴﾖﾆｹｹﾔ・ｯﾊ｣ｬﾊｹﾓﾃﾒﾑﾓﾐｵﾄｾﾘﾕｹｹﾔ・ ~Matrix(); //ﾎｹｺｯﾊ void setMatrix(const float *pvalue); // ｾﾘﾕｳｳｵ,ﾓﾃpvalueﾖｸﾏﾄﾄﾚｴ豼鯡ｾﾝﾎｪｾﾘﾕｳﾖｵ void printMatrix() const; // ﾏﾔﾊｾｾﾘﾕ・ inline float &element(int i, int j) //ｷｵｻﾘｾﾘﾕﾚiﾐﾐｵﾚjﾁﾐﾔｪﾋﾘｵﾄﾒﾓﾃ { float &q=p[(i-1)*lines+j-1]; return q; } inline float element(int i, int j) const// ｷｵｻﾘｾﾘﾕﾚiﾐﾐｵﾚjﾁﾐﾔｪﾋﾘｵﾄﾖｵ { return p[(i-1)*lines+j-1]; } void setElement(int i, int j, int value); //ﾉ靹ﾃｾﾘﾕﾚiﾐﾐｵﾚjﾁﾐﾔｪﾋﾘﾖｵﾎｪvalue inline int getLines() const; //ｷｵｻﾘｾﾘﾕﾐﾊ inline int getCols() const; //ｷｵｻﾘｾﾘﾕﾐﾊ private: int lines; // ｾﾘﾕﾐﾊ int cols; // ｾﾘﾕﾐﾊ float *p; // ﾖｸﾏ豺ﾅｾﾘﾕｾﾝｵﾄﾄﾚｴ豼魴ﾄﾊﾗｵﾘﾖｷ }; #endif
Matrix类的实现：
1 #include"matrix.h" 2 #include<iostream> 3 using namespace std; 4 Matrix::Matrix(int n) 5 { 6 lines=n; 7 cols=n; 8 p=new float[lines*cols]; 9 } 10 Matrix::Matrix(int m,int n) 11 { 12 lines=n; 13 cols=m; 14 p=new float[lines*cols]; 15 } 16 Matrix::Matrix(const Matrix &X) 17 { 18 int i; 19 lines=X.lines; 20 cols=X.cols; 21 p=new float[X.lines*X.cols]; 22 for(i=0;i<X.lines*X.cols;i++) 23 p[i]=X.p[i]; 24 } 25 Matrix::~Matrix() 26 { 27 delete []p; 28 } 29 void Matrix::setMatrix(const float *pvalue) 30 { 31 int i; 32 for(i=0;i<lines*cols;i++) 33 { 34 p[i]=pvalue[i]; 35 } 36 } 37 void Matrix::printMatrix() const 38 { 39 int i; 40 for(i=0;i<lines*cols;i++) 41 { 42 if((i%lines!=0||i==0)&&i!=lines*cols-1) 43 cout<<p[i]<<" "; 44 else if(i==lines*cols-1) 45 { 46 cout<<p[i]<<endl; 47 } 48 else 49 { 50 cout<<endl; 51 cout<<p[i]<<" "; 52 } 53 } 54 } 55 void Matrix::setElement(int i,int j,int value) 56 { 57 element(i,j)=value; 58 } 59 inline int Matrix::getCols() const 60 { 61 return cols; 62 } 63 inline int Matrix::getLines() const 64 { 65 return lines; 66 }
主函数：
#include"matrix.h" #include<iostream> using namespace std; int main() { int m,n,i,j,v,x,y; while(1) { cout<<"Please input the lines and cols:"; cin>>n>>m; Matrix a(n,m),b(n); if(m<=1||n<=1) { cout<<"Error!"<<endl; continue; } float p[m*n],q[n*n]; cout<<"Please input the elements of the matrix A:"<<endl; for(i=0;i<m*n;i++) { cin>>p[i]; } a.setMatrix(p); cout<<"Please input the elements of the matrix B:"<<endl; for(i=0;i<n*n;i++) { cin>>q[i]; } b.setMatrix(q); while(1) { cout<<"Press 1 to modify, press 2 to print, press 3 to change the matrix, press 4 to quit, please input a number:"; cin>>x; if(x==1) { while(1) { cout<<"Press 1 to modify the matrix A, press 2 to modify the matrix B, press 3 to back:"; cin>>y; if(y==1) { while(1) { cout<<"Please input the line, col and the value after modify of the Matrix A:"; cin>>i>>j>>v; if(i<=0||i>n||j<=0||j>m) { cout<<"Error!Please input again!"<<endl; } else { a.setElement(i,j,v); break; } } } else if(y==2) { while(1) { cout<<"Please input the line, col and the value after modify of the Matrix B:"; cin>>i>>j>>v; if(i<=0||i>n||j<=0||j>n) { cout<<"Error!Please input again!"<<endl; } else { b.setElement(i,j,v); break; } } } else if(y==3) { break; } else continue; } } else if(x==2) { cout<<"The Matrix A is:"<<endl; a.printMatrix(); cout<<"The Matrix B is:"<<endl; b.printMatrix(); } else if(x==3||x==4) { break; } else continue; } if(x==4) { break; } } return 0; }
运行结果：
PS：（1）.一张图装不下运行结果，所以运行结果分两张图表示（第一张图的最后两行与第二张图的前两行重合）
（2）.不知道怎么回事，注释中的汉字拷贝粘贴过来就会变成乱码（第二题的那个注释是我自己改成汉字的）。。。为了防止乱码影响其他同学的阅读，所以我删除了第一题（ex3）以及第四题第三小题（books类）中的注释。
4.期中考试习题：
（1）第一题代码：
#include<iostream> #include<cstdlib> using namespace std; class Dice { public: Dice(int n); int cast(); private: int sides; }; Dice::Dice(int n) { sides=n; } int Dice::cast() { int a=rand()%sides+1; return a; } int main() { int side,number,i,m,t=0; float p; cin>>side; Dice a(side); cin>>number; for(i=0;i<500;i++) { m=a.cast(); if(m==number) { t++; } } p=float(t)/500; cout<<p; return 0; }
第一题运行结果：
（2）第二题：
Users类的定义：
#include<iostream> #include<string> using namespace std; class Users { public: Users(string Name,string Password="111111"); void change(); void print(); void show(); private: int id; string name; string password; int static CurrentID; };
Users类的实现：
#include"users.h" #include<iostream> #include<string> using namespace std; int id; int Users::CurrentID=999; Users::Users(string Name,string Password) { CurrentID++; id=CurrentID; name=Name; password=Password; } void Users::change() { int count=0; string s; while(1) { cout<<"Please input the original password:"; cin>>s; if(s==password) { cout<<"You are correct!"<<endl; cout<<"Please input the new password:"; cin>>password; break; } else { if(count!=2) cout<<"You are wrong! Please try again:"; count++; } if(count==3) { cout<<"Please try again later."<<endl; break; } } } void Users::print() { cout<<"Current ID:"<<id<<" Name:"<<name<<" Password:"<<password<<endl; } void Users::show() { cout<<CurrentID<<endl; }
主函数：
#include"Users.h" #include<iostream> #include<vector> #include<string> using namespace std; int main() { int i,id,j; string Name,Password; vector<Users>users; while(1) { cout<<"Press 1 to insert; press 2 to modify; press 3 to print; press 4 to show; press 5 to end; Please input number:"; cin>>i; if(i==1) { cout<<"Name:"; cin>>Name; cout<<"Password:"; cin>>Password; Users u(Name,Password); users.push_back(u); } else if(i==2) { cout<<"Please input the id:"; cin>>id; users[id-1000].change(); } else if(i==3) { for(j=0;j<users.size();j++) { users[j].print(); } } else if(i==4) { users[i].show(); } else if(i==5) { break; } else continue; } return 0; }
运行结果：
（3）第三题：
Books类的定义：
#ifndef BOOK_H #define BOOK_H #include <string> using std::string; class Book { public: Book(string isbnX, string titleX, float priceX); //ｹｹﾔ・ｯﾊ void print(); // ｴ｡ﾍｼﾊ鰔ﾅﾏ｢ private: string isbn; string title; float price; }; #endif
Books类的实现：
#include "book.h" #include <iostream> #include <string> using namespace std; Book::Book(string isbnX,string titleX,float priceX) { isbn=isbnX; title=titleX; price=priceX; } void Book::print() { cout<<"Isbn:"<<isbn<<" Title:"<<title<<" Price:"<<price<<endl; }
主函数：
#include "book.h" #include <vector> #include <iostream> using namespace std; int main() { vector<Book>book; string isbn, title; float price; while(cin>>isbn>>title>>price) { Book b(isbn,title,price); book.push_back(b); } int i; for(i=0;i<book.size();i++) { book[i].print(); } return 0; }
运行结果：
二。实验总结与讨论：
通过这次实验，我在类的声明与实现以及构造函数这两个方面上实现了突破。但还是存在着一些不足：首先，编程速度太慢，反复调试次数太多。仅仅做期中考试那3道题就用了2个半小时，而考试时要求1小时完成，远远超出了考试要求的时间。其次，还有一些知识掌握的不太熟练，比如说深复制的应用以及vector类的应用。所以在这门学科上，以后还有很长的路要走。