Question

我在课堂上获得了一项任务：

编写一个程序，通过使用指针创建和管理数组。您的主程序应该只通过各种函数与指针/数组交互。然后，这些函数将限制阵列的使用以适当处理。例如，这些函数将消除超越数组边界的可能性。

到目前为止，我已经编写了程序并修复了大部分错误，但无论我尝试什么，我都会在“此范围内未声明函数”错误。该计划包括以下文件：main.cpp MyArray.cpp和MyArray.h

的main.cpp

#include <iostream>
#include "MyArray.h"

using namespace std;

int main(int argc, char * argv[]) {
    int *Array1, *Array2;
    int Array1Size(10), Array2Size(10);
    int Array1Value(0), Array2Value(0);

    cout << "Enter Size and Initial value for Array1: ";

    cin >> Array1Size >> Array1Value;

    cout << "Enter Size and Initial value for Array2: ";

    cin >> Array2Size >> Array2Value;

    CreateArray(Array1, Array1Size);
    InitArray(Array1, Array1Size, Array1Value);

    CreateArray(Array2, Array2Size);
    InitArray(Array2, Array2Size, Array2Value);

    cout << "Printing Array1:" << endl;
    PrintArray(Array1, Array1Size);
    cout << endl;
    cout << "Printing Array2:" << endl;
    PrintArray(Array2, Array2Size);
    cout << endl;

    if(CopyArray(Array1, Array1Size, Array2, Array2Size)) {
        cout << "Copy was successful" << endl;
    } else {
        cout << "Copy was not successful" << endl;
    }

    cout << "Printing Array1:" << endl;

    PrintArray(Array1, Array1Size);

    cout << endl;

    EnterArray(Array1, Array1Size);

    // MergeArray(Array1, Array1Size, Array2, Array2Size);

    cout << "Printing Array1:" << endl;
    PrintArray(Array1, Array1Size);

    cout << endl;

    return 0;
}

MyArray.h

#ifndef _MyArray_h_included_
#define _MyArray_h_included_

class MyArray
{
    public:
        void CreateArray(int *array, int size); 
        /*
        CreateArray(int *array, int size): Will accept a pointer to an array, and the size of the array and will allocate the appropriate amount of memory for the array
        */
        void InitArray(int *array, int size, int value);
        /*
        InitArray(Array1, Array1Size, Array1Value): Will initialize the contents of the arry Array1 to the value Array1Value
        */
        void PrintArray(int *array, int size);
        /*
        PrintArray(Array1, Array1Size): Will print the contest of the Array1
        */
        bool CopyArray(int *arrayOne, int sizeOne, int *arrayTwo, int sizeTwo);
        /*
        CopyArray(Array1, Arrary1Size, Array2, Array2Size): Will copy the contents of Array2 to Array1 iff the two arrays are of equal size. If the copying process is successfully completed, then a value of 1 is returned, otherwise a value of 0 is returned.
        */
        void EnterArray(int *array, int size);
        /*
        EnterArray(Array1, Array1Size): Will populate the Array1 from the stdin by prompting the user to enter all elements of the array.
        */
    };
#endif

MyArray.cpp

#include <iostream>
#include "MyArray.h"

using namespace std;

void MyArray::CreateArray(int *array, int size) {
    array = new int[size];
}

/*
CreateArray(int *array, int size): Will accept a pointer to an array, and the size of the array and will allocate the appropriate amount of memory for the array
*/
void MyArray::InitArray(int *array, int size, int value) {
    for(int index(0); index < size; index++) {
        array[index] = value;
    }
}

/*
InitArray(Array1, Array1Size, Array1Value): Will initialize the contents of the arry Array1 to the value Array1Value
*/
void MyArray::PrintArray(int *array, int size) {
    for(int index(0); index < size; index++) {
        cout << "Value of index: " << index << " is " << array[index] << endl;
    }
}

/*
PrintArray(Array1, Array1Size): Will print the contest of the Array1
*/
bool MyArray::CopyArray(int *arrayOne, int sizeOne, int *arrayTwo, int sizeTwo) {
    if(sizeOne != sizeTwo) {
        return false;
    } else {
        for(int index(0); index < sizeTwo; index++) {
            arrayOne[index] = arrayTwo[index];
        }

        return true;
    }
}

/*
CopyArray(Array1, Arrary1Size, Array2, Array2Size): Will copy the contents of Array2 to Array1 iff the two arrays are of equal size. If the copying process is successfully completed, then a value of 1 is returned, otherwise a value of 0 is returned.
*/
void MyArray::EnterArray(int *array, int size){
    int index(0);

    while(index < size) {
        int value(0);
        cout << "Enter the value for index: " << index + 1 << endl;
        cin >> value;
        array[index] = value;
    }
}
/*
EnterArray(Array1, Array1Size): Will populate the Array1 from the stdin by prompting the user to enter all elements of the array.
*/

我得到的错误类似于：main.cpp:'LineNumber': error. 'Every Function in MyArray.cpp' was not declared in this scope（我会复制粘贴确切的错误但我无法从我用来连接到远程主机的终端复制粘贴我编译我的代码）< / p>

我一直试图解决这个问题好几个小时，我无法弄清楚，我甚至看过其他Stack帖子，如'foo' was not declared in this scope c++
非常感谢任何帮助，谢谢。

此外，我没有写main.cpp，它是通过赋值给出的。

Answer 1

在C ++中，foo或A可以调用类A.foo()的函数A_ptr->foo()，只有foo()不起作用。

我认为你不需要这里的课，只需使用免费功能。

如果您确实想使用MyArray类，则无需在main.cpp中编写int *Array1, *Array2;并将其作为arg传递。最好将数组存储在MyArray类中。

就像这样。

的main.cpp

#include <iostream>
#include "MyArray.h"

using namespace std;

int main(int argc, char * argv[]) {
    //int *Array1, *Array2;
    MyArray Array1;

    int Array1Size(10);
    int Array1Value(0);

    cout << "Enter Size and Initial value for Array1: ";

    cin >> Array1Size >> Array1Value;

    Array1.CreateArray(Array1Size);
    Array1.InitArray(Array1Size, Array1Value);

    cout << "Printing Array1:" << endl;
    Array1.PrintArray(Array1Size);
    cout << endl;

    return 0;
}

MyArray.h

#ifndef _MyArray_h_included_
#define _MyArray_h_included_

class MyArray
{
    public:
        void CreateArray(int size); 

        void InitArray(int size, int value);

        void PrintArray(int size);

    private:
        int *m_array;

    };
#endif

MyArray.cpp

#include <iostream>
#include "MyArray.h"

using namespace std;

void MyArray::CreateArray(int size) {
    m_array = new int[size];
}


void MyArray::InitArray(int size, int value) {
    for(int index(0); index < size; index++) {
        m_array[index] = value;
    }
}


void MyArray::PrintArray(int size) {
    for(int index(0); index < size; index++) {
        cout << "Value of index: " << index << " is " << m_array[index] << endl;
    }
}

我忽略了解决方案中的一些函数以及析构函数，您应该使用delete[]

Answer 2

获取一本关于C ++的书并进行研究。您需要创建一个MyArray对象并使用对象调用函数：

MyArray myArr;

myArr.CreateArray(Array1, Array1Size);

等

如果给出main，则createArray必须在内部创建数组：

MyArray myArr;

void CreateArray(int *array, int size)
{
    return myArr.CreateArray(array, size);
}

Answer 3

首先，你已经了解了什么是类。在您调用MyArray函数的情况下，您必须拥有MyArray类的实例：

MyArray a;
a.CreateArray(...);
...

C ++“Function”未在此范围内声明

的main.cpp

MyArray.h

MyArray.cpp

3 个答案: