错误:内存位置的 std::length_error [英] Error : std::length_error at memory location

问题描述

当我调用转置函数时，出现此错误:错误:

When I call transpose function I got this error: Error :

std::length_error at memory location

我不知道到底是什么导致了错误

I do not know exactly what could cause the error

//class Matrix.h
class Matrix
{
private:
    std::vector<std::vector<double>> content;
    size_t numberOfRows;
    size_t numberOfColumns;
    double determinant;
};

inline Matrix::Matrix(size_t nRows, size_t nColumns)
    : content(nRows,std::vector<double>(nColumns)),
      numberOfRows(nRows), numberOfColumns(nColumns) {}

const double getValue(size_t i, size_t j) const { 
    return (i >= numberOfRows) || (j >= numberOfColumns) ? NULL : content[i][j]; 
}

void setValue(size_t i, size_t j, double value) {
    (i >= numberOfRows) || (j >= numberOfColumns) ? content[i][j] = NULL : content[i][j] = value;
    determinant = NULL;
}

Matrix Matrix::transpose()
{
    Matrix result(numberOfColumns, numberOfRows);
    for (size_t i = 0; i < numberOfRows; i++)
        for (size_t j = 0; j < numberOfColumns; j++)
            result.setValue(j, i, getValue(i, j));
    return result; /// Error here
}

推荐答案

解决方案是将对象作为指针返回或将变量作为引用传递，正确的例子如下:

The solution is return the object as a pointer or pass a variable as reference, here is the correct example:

Matrix* Matrix::transpose()
{
    Matrix *result=new Matrix(numberOfColumns, numberOfRows);
    for (size_t i = 0; i < numberOfRows; i++)
        for (size_t j = 0; j < numberOfColumns; j++)
            result.setValue(j, i, getValue(i, j));
    return result;
}

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