第7章 7-8题

第7题

#include<iostream>
const int MAX = 5;
using namespace std;
const double* fill_array(double ar[] , int limit);  //填充数组函数
void show_array(const double ar[] , const double* last);  //显示数组
void change_array(int r , double ar[] , const double* last);
int main()
{
  double oldHouse[MAX];
  const double* lastHouse = fill_array(oldHouse,MAX);  //填充
  show_array(oldHouse,lastHouse);  //第一次显示
  change_array(3,oldHouse,lastHouse);  //因子随便选了个数字3，只是为了说明程序功能
  show_array(oldHouse,lastHouse);  //显示X因子后的数组
  return 0;
}
const double* fill_array(double ar[] , int limit)
{
  double num = 0;
  int size = 0;
  for(int i = 0 ; i < limit ; ++i)
   {
     cout<<"请输入第"<<i+1<<"个数.";
     cin>>num;
     if(!cin)            //判断输入是否位double,如果输入非法结束
      {
       cin.clear();
       while(cin.get() != '\n')
        continue;
       cout<<"输入非法数据，填充结束\n";
       ar[size] = 0;  //这两行作用：第一个输入为非法，则该数组默认第一个数值位0，避免段错误，下同
       ++size;        //这两行如果注释掉，那第一个输入错误或为负，程序就会出错
       break; 
      }
     else if(num < 0)    //输入负数，控制结束
      {
        cout<<"数组填充完成.\n";
        ar[size] = 0;  //同上
        ++size;
        break;
      }
     ar[size] = num;
     ++size;
   }
 return &(ar[size-1]);
}
void show_array(const double ar[] , const double* last)
{
  cout<<"显示数组\n";
  const double* mid = ar;
  for(int i = 0 ;  ; ++i)  //省略掉判断条件，作为无限循环
   {
    cout<<"第"<<i+1<<"个数为"<<ar[i]<<endl;
    if((mid+i) == last)
     break;
   }
}
void change_array(int r , double ar[] , const double* last)
{
  for(int i = 0 ; ; ++i)
   {
     ar[i] *= r;
     if(ar+i == last)
      break;
   }
}

第8题 第1小题

#include<iostream>
using namespace std;
const int season = 4;
const char* seasonName[season] = {"Sprint","Summer","Fall","Winner"};  //c++11
void fillArray(double* arr , int season);
void showArray(const double* arr , int season); 
int main()
{
  double InSeason[season];
  fillArray(InSeason,season);
  showArray(InSeason,season);
 return 0;
}
void fillArray(double* arr , int season)
{
  for(int i = 0 ; i < season ; ++i)
  { 
   cout<<"请输入"<<*(seasonName+i)<<"的收入.";
   cin>>*(arr+i);
  }
}
void showArray(const double* arr , int season)
{
  double cost = 0;
  for(int i = 0 ; i < season ; ++i)
   {
    cout<<*(seasonName+i)<<"收入为"<<*(arr+i)<<"\n";
    cost += *(arr+i);
   }
  cout<<"总收入:"<<cost;
}

第8题第2小题

#include<iostream>
using namespace std;
const int season = 4;
const char* seasonName[season] = {"Sprint","Summer","Fall","Winner"};
struct inCome
{
  double takeIn[season];
};
void fillArray(inCome* re);
void showArray(const inCome* re);
int main()
{
  inCome gets;
  fillArray(&gets);
  showArray(&gets);
  return 0;
}
void fillArray(inCome* re)
{
  for(int i = 0 ; i < season ; ++i)
   {
    cout<<"请输入"<<*(seasonName+i)<<"的收入:";
    cin>>re->takeIn[i];
   }
}
void showArray(const inCome* re)
{
  double cost = 0;
  for(int i = 0 ; i < season ; ++i)
  {
    cout<<*(seasonName+i)<<"的收入为"<<re->takeIn[i]<<endl;
    cost += re->takeIn[i];
  }
  cout<<"总收入为"<<cost;
}