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  1. class Student
  2. {
  3. public:
  4.     // If you can, don't use numbers: 
  5.     // you have a 3 on the variable,
  6.     // a 3 on the function, etc.
  7.     // Use a #define on C or a static const on C++
  8.     static const int SIZE= 3;
  9.     // You can also use it outside the class as Student::SIZE
  10.  
  11. public:
  12.     void SetDaysToCompleteCourse(int* newDaysToCompleteCourse);
  13.     // Safer version:
  14.     void SetDaysToCompleteCourseSafe(int (&newDaysToCompleteCourse)[SIZE])
  15.     {
  16.     	SetDaysToCompleteCourse(newDaysToCompleteCourse);
  17.     }
  18.  
  19.     // The consts are for "correctness"
  20.     const int* GetDaysToCompleteCourse() const; // Ditto @ above comment.
  21.  
  22.     Student()
  23.     {
  24.         // Always initialize variables
  25.         for (int i= 0; i < SIZE; i++) {
  26.             daysToCompleteCourse[i]= 0;
  27.         }
  28.     }
  29.  
  30. private:
  31.     int daysToCompleteCourse[SIZE];
  32.     // On GCC, you can do
  33.     //int daysToCompleteCourse[SIZE]{};
  34.     // Which will allow you not to specify it on the constructor
  35. };
  36.  
  37. void Student::SetDaysToCompleteCourse(int* newDaysToCompleteCourse) 
  38. {
  39.     // It's not wrong, just that
  40.     // this->daysToCompleteCourse[0] = daysToCompleteCourse[0];
  41.     // use another name like newDaysToCompleteCourse and then you can suppress this->
  42.     // And use a for loop
  43.     for (int i= 0; i < SIZE; i++) {
  44.         daysToCompleteCourse[i]= newDaysToCompleteCourse[i];
  45.     }
  46. }
  47.  
  48. const int* Student::GetDaysToCompleteCourse() const
  49. {
  50.     return daysToCompleteCourse;
  51. }
  52.  
  53. #include <iostream>
  54.  
  55. std::ostream& operator<<(std::ostream& stream, const Student& student)
  56. {
  57.     const int* toShow= student.GetDaysToCompleteCourse();
  58.     for (int i= 0; i < Student::SIZE; i++) {
  59.         stream << toShow[i] << ' ';
  60.     }
  61.     return stream;
  62. }
  63.  
  64. int main()
  65. {
  66.     Student student;
  67.     int daysToCompleteCourse[3] = { 1, 2, 3 };
  68.     int daysToCompleteCourseBad[2] = { 1, 2 };
  69.     // You don't need this
  70.     //int* ptr = daysToCompleteCourse;
  71.     //student.SetDaysToCompleteCourse(ptr);
  72.     //You can just do:
  73.     student.SetDaysToCompleteCourse(daysToCompleteCourse);
  74.     student.SetDaysToCompleteCourseSafe(daysToCompleteCourse);
  75.  
  76.     // This would work but what's the number stored on the third element?
  77.     // student.SetDaysToCompleteCourse(daysToCompleteCourseBad);
  78.     // Safe version takes a reference to a 3 element array (no more, no less)
  79.     // This will not work:
  80.     // student.SetDaysToCompleteCourseSafe(daysToCompleteCourseBad);
  81.  
  82.     // On C++ int* is "a pointer to an int"
  83.     // It doesn't specify how many of them
  84.     // Arrays are represented just by the pointer to the first element
  85.     // It's the FASTEST and CHEAPEST way... but you need the SIZE
  86.     const int* toShow= student.GetDaysToCompleteCourse();
  87.     for (int i= 0; i < Student::SIZE; i++) {
  88.         std::cout << toShow[i] << ' ';
  89.     }
  90.     std::cout << std::endl;
  91.  
  92.     // Or you can do:
  93.     std::cout << student << std::endl;
  94. }
Success #stdin #stdout 0s 15232KB
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https://ideone.com/DeJ2Nt
language:
C++ (gcc 8.3)
created:
5 years ago
visibility:
public

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