4. (20 scores)

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类的基础语法, 类层次, 虚函数调用, 资源

Programming for under graduate students graduation audits: read basic information, according to the requirements of graduation audit, output the information into studentGradutate.data file.

Among them, under graduate students are required to complete at least 150 credits, and graduate students are required to complete at least 36 credits, and pass both teaching practice and scientific research assessement.

The contents of the question include:

UStudent

string strId;     // Student number
string strNames;  // Student name
double dCredits;  // Credits completed
bool bResult;     // Can graduate or not

GStudent

string strId;     // Student number
string strNames;  // Student name
double dCredits;  // Credits completed
bool bResult;     // Can graduate or not
bool bTeaching;   // Pass teaching practice or not
bool bResearch;   // Pass scientific research assessement or not

Complete the following classes called Student, UStudent, GStudent, and the main function, so that the program can create a studentGraduate.data file as following correctly:

#include <fstream>
#include <string>
#include <vector>

class Student {
 public:
  // ...

 private:
  std::string strId;
  std::string strName;
};

class UStudent : public Student {
 public:
  // ...

 private:
  double dCredits;
  bool bResult;
};

class GStudent : public UStudent {
 public:
  // ...

 private:
  double bTeaching;
  bool bResearch;
};

int main() {
  std::vector<Student*> s(4);
  s[0] = new UStudent(1001, "Donald", 156, 1);
  s[1] = new UStudent(1002, "Vivion", 142, 0);
  s[2] = new GStudent(2003, "Chris", 36, 1, 1, 1);
  s[3] = new GStudent(2004, "Cindy", 38, 1, 1, 1);

  // output the information of students in to "studentGraduate.data" file
  //according to the bResult data

  { /* fill the blanks here */ }

  for (int i = 0; i < s.size(); i++) {
    delete s[i];
  }
}

studentGraduate.data

1001 Donald 156 1
2003 Chris 36 1 1 1
2004 Cindy 38 1 1 1

翻译

编写实现学生的毕业审查: 读取基本信息, 根据毕业审查要求, 输出信息到 studentGradutate.data 文件中.

其中, 本科学生要求修满至少 150 学分; 研究生要求修满至少 36 学分, 并通过教学实践和科研实践考核.

该问题涉及以下内容:

UStudent

string strId;     // 学号
string strNames;  // 学生名字
double dCredits;  // 完成的学分数
bool bResult;     // 能否毕业

GStudent

string strId;     // 学号
string strNames;  // 学生名字
double dCredits;  // 完成的学分数
bool bResult;     // 能否毕业
bool bTeaching;   // 是否通过教学实践
bool bResearch;   // 是否通过科研实践

完成以下类 Student, UStudent, GStudent 和 main 函数的编写, 以让程序创建一个 studentGraduate.data 文件含有以下内容:

#include <fstream>
#include <string>
#include <vector>

class Student {
 public:
  // ...

 private:
  std::string strId;
  std::string strName;
};

class UStudent : public Student {
 public:
  // ...

 private:
  double dCredits;
  bool bResult;
};

class GStudent : public UStudent {
 public:
  // ...

 private:
  double bTeaching;
  bool bResearch;
};

int main() {
  std::vector<Student*> s(4);
  s[0] = new UStudent(1001, "Donald", 156, 1);
  s[1] = new UStudent(1002, "Vivion", 142, 0);
  s[2] = new GStudent(2003, "Chris", 36, 1, 1, 1);
  s[3] = new GStudent(2004, "Cindy", 38, 1, 1, 1);

  // 根据 bResult 数据, 将学生输出到 "studentGraduate.data" 文件中

  { /* 补全此处的代码 */ }

  for (int i = 0; i < s.size(); i++) {
    delete s[i];
  }
}

studentGraduate.data

1001 Donald 156 1
2003 Chris 36 1 1 1
2004 Cindy 38 1 1 1

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[在线代码 x58TxMz53]

这道题注意一下, 21 年最后一道题也考了类似的题。

此题中确切给出了输出文件的输出内容, 故虽然输出文件以看似很二进制的 .data 为后缀, 但不是二进制输出.