Question

所以基本上我做了一个2-D数组，Component pixel[][]，Component是类，我试图改变网格的一个变量（由维度的值组成）。出于某种原因，当我运行代码时，除了其中一个代码之外，大部分代码都打印出0和1。

class Component {
public:
    int label;
    int order;
};

int main() {
    int dimension;
    float density;
    float R;

    do
    {
        cout << "Please enter a grid size between 5 and 15: ";
        cin >> dimension;
        if(dimension > 15 || dimension < 5)
        {
            cout << "Needs to be between 5 and 15" << endl;
        }
    }while(dimension > 15 || dimension < 5);

    do
    {
        cout << "Enter a density value between 0.0 and 1.0: ";
        cin >> density;
        if(density > 1.0 || density < 0.0)
        {
            cout << "Needs to be between 0.0 and 1.0" << endl;
        }
    }while(density > 1.0 || density < 0.0);

    Component pixel[dimension][dimension];

    srand (unsigned(time(NULL)));
    for (int row = 1; row <= dimension; row++)
    {
        for (int col = 1; col <= dimension; col++)
        {
            R = (float)rand()/(RAND_MAX+1);
            cout << R << " ";
            if (R < density)
            {
                pixel[row][col].label = 1;
            }
            else
                pixel[row][col].label = 0;
        }
        cout << endl;
    }
    cout << endl << endl;

    for (int row = 1; row <= dimension; row++)
    {
        for (int col = 1; col <= dimension; col++)
        {
            cout << pixel[row][col].label << " ";
        }
        cout << endl;
    }
    return 0;   
}

Answer 1

从https://stackoverflow.com/a/31090156/3349368看，请尝试使用STL 30/10/2015。

从上面的链接

std::vector<std::vector<Component> >

只需将int no_of_cols = 5; int no_of_rows = 10; int initial_value = 0; std::vector<std::vector<int>> matrix; matrix.resize(no_of_rows, std::vector<int>(no_of_cols, initial_value)); // Read from matrix. int value = matrix[1][2]; // Save to matrix. matrix[3][1] = 5;替换为int

即可

Answer 2

当我学到很难的方法时，必须在编译时知道数组大小。您不允许cin＆gt;＆gt;数组大小并在运行时设置它们。它们必须是const int，在代码中明确声明。如上所述，如果您希望能够在运行时更改其大小，请使用std :: vector，因为它们是动态的，而不是静态的。

使用类中的属性创建一个2D数组，在更改值时遇到麻烦

2 个答案: