计算机与程序设计(C++)实验指导书4_2015秋

《计算机与程序设计(C++)》实验指导书2015年12月实验四指针与结构体1、实验目的（1）了解动态内存分配，学会使用动态变量和动态数组（2）会使用数组的指针和指向的指针变量（3）学习定义结构体、结构体变量、结构体数组（4）进一步掌握函数编写（5）掌握运算符”.”的应用。

（6）学习C++语言菜单设计的一般方法（7）初步学习开发一个小型实用系统的方法（8）学会调试一个较长程序的基本方法2、实验设备使用PC机、操作系统Window 7、Visual C++ 6.03、实验基本原理程序设计的基本原理4、实验内容输入以下三个程序段，按红色注释补充代码。

（1）// This program demonstrates the use of dynamic arrays#include <iostream>#include <iomanip>using namespace std;int main( ){float *monthSales; // a pointer used to point to an array holding monthly salesfloat total = 0; // total of all salesfloat average; // average of monthly salesint numOfSales; // number of sales to be processedint count; // loop countercout << setiosflags(ios::fixed)<< setprecision(2);cout << "How many monthly sales will be processed? ";cin >> numOfSales;// Fill in the code to allocate memory for the array pointed to by monthSales.if ( // Fill in the condition to determine if memory has been allocated (or eliminate this if construct if your instructor tells you it is not needed for your compiler)){cout << "Error allocating memory!\n";return 0;}cout << "Enter the sales below\n";for (count = 0; count < numOfSales; count++){cout << "Sales for Month number "<<// Fill in code to show the number of the month<< ":";// Fill in code to bring sales into an element of the array }for (count = 0; count < numOfSales; count++){total = total + monthSales[count];}average = // Fill in code to find the averagecout << "Average Monthly sale is $" << average << endl;// Fill in the code to deallocate memory assigned to the array.return 0;}Sample Run:How many monthly sales will be processed 3Enter the sales belowSales for Month number 1: 401.25Sales for Month number 2: 352.89Sales for Month number 3: 375.05Average Monthly sale is $376.40// This program demonstrates the use of dynamic arrays程序演示使用了动态数组#include <iostream>#include <iomanip>using namespace std;int main( ){float total = 0; // total of all salesfloat average; // average of monthly salesint numOfSales; // number of sales to be processedint count; // loop countercout << setiosflags(ios::fixed)<< setprecision(2);cout << "How many monthly sales will be processed? ";cin >> numOfSales;// Fill in the code to allocate memory for the array pointed to by monthSales.填写代码为指向数组的monthSales分配内存float *monthSales=new float[12] ;if (monthSales==NULL)// Fill in the condition to determine if memory has been allocated (or eliminate this if construct if your instructor tells you it is not needed for your compiler){cout << "Error allocating memory!\n";return 0;}cout<<"Enter the sales below"<<endl;for (count = 0; count < numOfSales; count++){cout << "Sales for Month number "<< count+1// Fill in code to show the number of the month<< ":";// Fill in code to bring sales into an element of the arraycin>>monthSales[count];}for (count = 0; count < numOfSales; count++){total = total + monthSales[count];}average =total/numOfSales;// Fill in code to find the averagecout << "Average Monthly sale is $" << average << endl;// Fill in the code to deallocate memory assigned to the array.delete [] monthSales;return 0;}（2）reverse函数实现逆序排列。

函数原型：void reverse(int * pa, int n);{//reverse process}主调函数：int main(){Int *a; // a pointer variableint n;cin>>n;a=new int [n]; // allocation of the array which has n elements //input the array;reverse(a,n) // call to the function//output the a arraydelete []a;return 0;}/*（2）reverse函数实现逆序排列。

函数原型：*/#include <iostream>using namespace std;void reverse(int * pa, int n){//reverse processint i,j,t;for(j=1;j<=n-1;j++)for(i=1;i<n-j+1;i++)if(pa[i-1]<pa[i]){t=pa[i-1];pa[i-1]=pa[i];pa[i]=t;}}//主调函数：int main(){int *a; // a pointer variableint n,i;cin>>n;a=new int [n]; // allocation of the array which has n elements for(i=0;i<n;i++)cin>>a[i]; //input the array;reverse(a,n); // call to the functionfor(i=0;i<n;i++) //output the a arraycout<<a[i]<<" ";delete []a;return 0;}（3）迷你型电话通讯录管理系统具有输入、查询、显示、退出等功能。

输入功能：可以完成电话通讯录的输入。

查询功能：完成按姓名查找电话号码，并显示电话号码。

显示功能：可以显示所有电话通讯录。

程序代码如下：#include <iostream>#include <iomanip>using namespace std;//定义含有姓名和电话号码的结构体int n=0; //n为电话通讯录记录数void menu(){cout<<"\t\t欢迎进入迷你电话通讯录管理系统"<<endl;cout<<"***************************MENU*****************************"<<endl;cout<<"*** 1. 输入电话通讯录记录***"<<endl;cout<<"*** 2. 按姓名查找电话通讯录记录***"<<endl;cout<<"*** 3. 显示所有电话通讯录记录***"<<endl;cout<<"*** 0. 退出***"<<endl;cout<<"************************************************************"<<endl;}//输入电话通讯录记录的函数//按名字查找电话通讯录记录的函数//输出所有通讯录记录的函数int main(){int key=1;//定义所需要的变量while(1){system("cls");menu();cout<<"请输入数字功能键：";cin>>key;switch(key){case 1://调用输入函数break;case 2:if(n==0) cout<<"空记录"<<endl;else //调用查找函数break;case 3:if(n==0) cout<<"空记录"<<endl;else //调用输出函数break;case 0:cout<<"欢迎下次使用！"<<endl; return 0;default:cout<<"数字功能键输入错误，请重新输入！"<<endl;}system("pause");}return 0;}5、实验步骤按实验一的编辑、编译、执行与调试过程。