CODEWITHSUNDEEP
c++arraysqtqvector
massaimara98
massaimara98

Reputation: 7459

QVector of arrays in C++

I'm trying to hold polynomial coefficients in QVector. My polynomials are of degree 2, so it has three numbers.

When I define QVector<double[3]> zeros_Real(n + 1) I get an error (below). First, I thought I could use QVector<QVector<double>> but it will be speed and memory problem, so I decided to not do that.

Why can't I have a QVector of double[3] elements?

The error:

mingw32-make[1]: *** [debug/main.o] Error 1
mingw32-make: *** [debug] Error 2
21:27:01: The process "C:\Qt\Tools\mingw492_32\bin\mingw32-make.exe" exited with code 2.
Error while building/deploying project untitled11 (kit: Desktop Qt 5.5.1 MinGW 32bit)
When executing step "Make"

Upvotes: 0

Views: 1538

Answers (1)

LogicStuff
LogicStuff

Reputation: 19607

QVector (like std::vector) requires its elements to be copyable (it has to copy the elements during reallocation). Arrays can not be copied, that implies you can't have QVector<double[3]>.

The working alternative is to use std::array (C++11 or later):

QVector<std::array<double, 3>>

Which can be copied. Qt doesn't have its own QArray, so you have to mix the standard library and Qt containers like this.

Upvotes: 5

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