C++:数组的setter和getter
我正在努力找到正确的格式来初始化类内的私有数组,并从类外获取/设置值 我的代码是半功能的,但在格式不正确的情况下感觉很尴尬。 它只返回数组的第一个元素,我希望它返回所有内容。阅读代码注释了解更多详细信息 注意:这是我为学校做的一个项目的一小部分——必须使用数组,而不是向量或列表 学生 student.cpp 控制台应用程序1.cpp 我尽了最大努力,但我想我需要朝着正确的方向轻推。 如果您有任何建议,我们将不胜感激。我想说:C++:数组的setter和getter,c++,arrays,getter-setter,C++,Arrays,Getter Setter,我正在努力找到正确的格式来初始化类内的私有数组,并从类外获取/设置值 我的代码是半功能的,但在格式不正确的情况下感觉很尴尬。 它只返回数组的第一个元素,我希望它返回所有内容。阅读代码注释了解更多详细信息 注意:这是我为学校做的一个项目的一小部分——必须使用数组,而不是向量或列表 学生 student.cpp 控制台应用程序1.cpp 我尽了最大努力,但我想我需要朝着正确的方向轻推。 如果您有任何建议,我们将不胜感激。我想说: // student.h class Student { public
// student.h
class Student
{
public:
// If you can, don't use numbers:
// you have a 3 on the variable,
// a 3 on the function, etc.
// Use a #define on C or a static const on C++
static const int SIZE= 3;
// You can also use it outside the class as Student::SIZE
public:
void SetDaysToCompleteCourse(int* daysToCompleteCourse);
// The consts are for "correctness"
// const int* means "don't modify this data" (you have a setter for that)
// the second const means: this function doesn't modify the student
// whithout the const, student.GetDaysToCompleteCourse()[100]= 1 is
// "legal" C++ to the eyes of the compiler
const int* GetDaysToCompleteCourse() const; // Ditto @ above comment.
Student()
{
// Always initialize variables
for (int i= 0; i < SIZE; i++) {
daysToCompleteCourse[i]= 0;
}
}
private:
int daysToCompleteCourse[SIZE];
// On GCC, you can do
//int daysToCompleteCourse[SIZE]{};
// Which will allow you not to specify it on the constructor
};
// student.cpp
void Student::SetDaysToCompleteCourse(int* newDaysToCompleteCourse)
{
// It's not wrong, just that
// this->daysToCompleteCourse[0] = daysToCompleteCourse[0];
// use another name like newDaysToCompleteCourse and then you can suppress this->
// And use a for loop
for (int i= 0; i < SIZE; i++) {
daysToCompleteCourse[i]= newDaysToCompleteCourse[i];
}
}
const int* Student::GetDaysToCompleteCourse() const
{
return daysToCompleteCourse;
}
// main.cpp
#include <iostream>
std::ostream& operator<<(std::ostream& stream, const Student& student)
{
const int* toShow= student.GetDaysToCompleteCourse();
for (int i= 0; i < Student::SIZE; i++) {
stream << toShow[i] << ' ';
}
return stream;
}
int main()
{
Student student;
int daysToCompleteCourse[3] = { 1, 2, 3 };
// You don't need this
//int* ptr = daysToCompleteCourse;
//student.SetDaysToCompleteCourse(ptr);
//You can just do:
student.SetDaysToCompleteCourse(daysToCompleteCourse);
// On C++ int* is "a pointer to an int"
// It doesn't specify how many of them
// Arrays are represented just by the pointer to the first element
// It's the FASTEST and CHEAPEST way... but you need the SIZE
const int* toShow= student.GetDaysToCompleteCourse();
for (int i= 0; i < Student::SIZE; i++) {
std::cout << toShow[i] << ' ';
// Also works:
//std::cout << student.GetDaysToCompleteCourse()[i] << ' ';
}
std::cout << std::endl;
// Or you can do: (because we defined operator<< for a ostream and a Student)
std::cout << student << std::endl;
}
你可以在这里现场查看:我想说:
// student.h
class Student
{
public:
// If you can, don't use numbers:
// you have a 3 on the variable,
// a 3 on the function, etc.
// Use a #define on C or a static const on C++
static const int SIZE= 3;
// You can also use it outside the class as Student::SIZE
public:
void SetDaysToCompleteCourse(int* daysToCompleteCourse);
// The consts are for "correctness"
// const int* means "don't modify this data" (you have a setter for that)
// the second const means: this function doesn't modify the student
// whithout the const, student.GetDaysToCompleteCourse()[100]= 1 is
// "legal" C++ to the eyes of the compiler
const int* GetDaysToCompleteCourse() const; // Ditto @ above comment.
Student()
{
// Always initialize variables
for (int i= 0; i < SIZE; i++) {
daysToCompleteCourse[i]= 0;
}
}
private:
int daysToCompleteCourse[SIZE];
// On GCC, you can do
//int daysToCompleteCourse[SIZE]{};
// Which will allow you not to specify it on the constructor
};
// student.cpp
void Student::SetDaysToCompleteCourse(int* newDaysToCompleteCourse)
{
// It's not wrong, just that
// this->daysToCompleteCourse[0] = daysToCompleteCourse[0];
// use another name like newDaysToCompleteCourse and then you can suppress this->
// And use a for loop
for (int i= 0; i < SIZE; i++) {
daysToCompleteCourse[i]= newDaysToCompleteCourse[i];
}
}
const int* Student::GetDaysToCompleteCourse() const
{
return daysToCompleteCourse;
}
// main.cpp
#include <iostream>
std::ostream& operator<<(std::ostream& stream, const Student& student)
{
const int* toShow= student.GetDaysToCompleteCourse();
for (int i= 0; i < Student::SIZE; i++) {
stream << toShow[i] << ' ';
}
return stream;
}
int main()
{
Student student;
int daysToCompleteCourse[3] = { 1, 2, 3 };
// You don't need this
//int* ptr = daysToCompleteCourse;
//student.SetDaysToCompleteCourse(ptr);
//You can just do:
student.SetDaysToCompleteCourse(daysToCompleteCourse);
// On C++ int* is "a pointer to an int"
// It doesn't specify how many of them
// Arrays are represented just by the pointer to the first element
// It's the FASTEST and CHEAPEST way... but you need the SIZE
const int* toShow= student.GetDaysToCompleteCourse();
for (int i= 0; i < Student::SIZE; i++) {
std::cout << toShow[i] << ' ';
// Also works:
//std::cout << student.GetDaysToCompleteCourse()[i] << ' ';
}
std::cout << std::endl;
// Or you can do: (because we defined operator<< for a ostream and a Student)
std::cout << student << std::endl;
}
你可以在这里现场查看:刚刚添加了一些我忘记包含在问题中的源代码。刚刚添加了一些我忘记包含在问题中的源代码。
#include "pch.h"
#include <iostream>
#include "student.h"
int main()
{
Student student;
int daysToCompleteCourse[3] = { 1, 2, 3 };
int* ptr = daysToCompleteCourse;
student.SetDaysToCompleteCourse(ptr);
std::cout << *student.GetDaysToCompleteCourse(); // returns first element of the array (1).
}
// student.h
class Student
{
public:
// If you can, don't use numbers:
// you have a 3 on the variable,
// a 3 on the function, etc.
// Use a #define on C or a static const on C++
static const int SIZE= 3;
// You can also use it outside the class as Student::SIZE
public:
void SetDaysToCompleteCourse(int* daysToCompleteCourse);
// The consts are for "correctness"
// const int* means "don't modify this data" (you have a setter for that)
// the second const means: this function doesn't modify the student
// whithout the const, student.GetDaysToCompleteCourse()[100]= 1 is
// "legal" C++ to the eyes of the compiler
const int* GetDaysToCompleteCourse() const; // Ditto @ above comment.
Student()
{
// Always initialize variables
for (int i= 0; i < SIZE; i++) {
daysToCompleteCourse[i]= 0;
}
}
private:
int daysToCompleteCourse[SIZE];
// On GCC, you can do
//int daysToCompleteCourse[SIZE]{};
// Which will allow you not to specify it on the constructor
};
// student.cpp
void Student::SetDaysToCompleteCourse(int* newDaysToCompleteCourse)
{
// It's not wrong, just that
// this->daysToCompleteCourse[0] = daysToCompleteCourse[0];
// use another name like newDaysToCompleteCourse and then you can suppress this->
// And use a for loop
for (int i= 0; i < SIZE; i++) {
daysToCompleteCourse[i]= newDaysToCompleteCourse[i];
}
}
const int* Student::GetDaysToCompleteCourse() const
{
return daysToCompleteCourse;
}
// main.cpp
#include <iostream>
std::ostream& operator<<(std::ostream& stream, const Student& student)
{
const int* toShow= student.GetDaysToCompleteCourse();
for (int i= 0; i < Student::SIZE; i++) {
stream << toShow[i] << ' ';
}
return stream;
}
int main()
{
Student student;
int daysToCompleteCourse[3] = { 1, 2, 3 };
// You don't need this
//int* ptr = daysToCompleteCourse;
//student.SetDaysToCompleteCourse(ptr);
//You can just do:
student.SetDaysToCompleteCourse(daysToCompleteCourse);
// On C++ int* is "a pointer to an int"
// It doesn't specify how many of them
// Arrays are represented just by the pointer to the first element
// It's the FASTEST and CHEAPEST way... but you need the SIZE
const int* toShow= student.GetDaysToCompleteCourse();
for (int i= 0; i < Student::SIZE; i++) {
std::cout << toShow[i] << ' ';
// Also works:
//std::cout << student.GetDaysToCompleteCourse()[i] << ' ';
}
std::cout << std::endl;
// Or you can do: (because we defined operator<< for a ostream and a Student)
std::cout << student << std::endl;
}