第7章 9-10题

第9题

#include<iostream>
using namespace std;
const int maxLen = 30;
struct student
{
  char fullName[maxLen];
  char hobby[maxLen];
  int oopLevel;
};
int getInfo(student* pa , int lenght);
void display_1(student someone);
void display_2(const student* someone);
void display_3(const student* allStudent , int nu);
int main()
{
  int sizeOfClass = 0;
  cout<<"请输入学生人数:";
  cin>>sizeOfClass;
  student* myClass = new student[sizeOfClass];
  int nus = getInfo(myClass,sizeOfClass);
  for(int i = 0 ; i < nus ; ++i)
  {
   cout<<"第"<<i+1<<"个学生信息."<<endl;
   display_1(*(myClass+i));
   display_2(myClass+i);
  }
  display_3(myClass,nus);
  delete [] myClass;
 return 0;
}
int getInfo(student* pa , int lenght)
{
  int realSize = 0;
  char goEnd = 'q';
  cout<<"学生信息录入，输入 'q' 退出输入.\n";
  for(int i = 0 ; i < lenght ; ++i)
  {
    cin.get();
    cout<<"请输入第"<<i+1<<"个学生的姓名";
    cin.getline((pa+i)->fullName,maxLen);
    if(*((pa+i)->fullName) == goEnd)   //是否结束输入
     break;

    cout<<"请输入第"<<i+1<<"个学生的爱好.";
    cin.getline((pa+i)->hobby,maxLen);
    if(*((pa+i)->hobby) == goEnd)
     break;

    cout<<"请输入第"<<i+1<<"个学生的成绩.";
    if(!(cin >> ((pa+i)->oopLevel)))
     break;                //输入不为整数也被认为结束输入

    if((pa+i)->oopLevel < 0)
     break;  //输入的成绩小于0，结束输入
    
    ++realSize;
   }
  return realSize;
}
void display_1(student someone)
{
  cout<<"姓名:"<<someone.fullName<<endl;
  cout<<"爱好:"<<someone.hobby<<endl;
  cout<<"成绩:"<<someone.oopLevel<<endl;
}
void display_2(const student* someone)
{
  cout<<"姓名:"<<someone->fullName<<endl;
  cout<<"爱好:"<<someone->hobby<<endl;
  cout<<"成绩:"<<someone->oopLevel<<endl;
}
void display_3(const student* allStudent , int nu)
{
  for(int i = 0 ; i < nu ; ++i)
   {
    cout<<"第"<<i+1<<"名学生信息."<<endl;
    cout<<"姓名:"<<(allStudent+i)->fullName<<endl;
    cout<<"爱好:"<<(allStudent+i)->hobby<<endl;
    cout<<"成绩:"<<(allStudent+i)->oopLevel<<endl;
   }
}

第10题

#include<iostream>
double add(double x , double y);  //求和
double qtc(double x, double y);  //求乘积
double calculate(double x , double y , double (*pt)(double , double ));
int main()
{
  using namespace std;
  double X = 0;
  double Y = 0;
  cout<<"请输入2个数字";
  while(cin>>X and cin>>Y)
   {
    cout<<"两数之和为"<<calculate(X,Y,add)<<endl;
    cout<<"两数乘积为"<<calculate(X,Y,qtc)<<endl;
    cout<<"请输入2个数字";
   }
  cout<<"Bye!";
 return 0;
}
double add(double x , double y)
{
  return x+y;
}
double qtc(double x , double y)
{
  return x*y;
}
double calculate(double x , double y , double (*pt)(double , double ))
{
  return (*pt)(x,y);
}