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c++functionstdoptional

Writing functions which handle invalid inputs in C++

In C++, how to handle function outputs , if the inputs are invalid. Say, I am writing a function to multiply two matrices. How to deal with it if the two matrices cannot be multiplied (due to in-compatible shape)?

I tried to use std::optional , but then it has created other problems. Since the output is expected to be std::optional(Matrix) ,I have to write all the other functions in the class (like print Matrix()) with the expected output as std::optional , which seems unnecessary.

Solution

  • I think this could be fun. Just add a 'valid' property to the Matrix and check it only when you want to!

    class Matrix
{
public:
    Matrix Multiply(Matrix other)
    {
       return Multiply(other, m_isValid);
    }

    bool IsValid()
    {
        return m_isValid;
    }

private:
    bool m_isValid;
    Matrix Multiply(Matrix other, bool& isValid);
};