README-container-inside-loop.md

container-inside-loop

Finds places defining containers inside loops. Defining them outside the loop and using resize(0) will save memory allocations.

Example

// This will allocate memory at least N times:
for (int i = 0; i < N; ++i) {
    QVector<int> v;
    (...)
    v.append(bar);
    (...)
}

// This will reuse previously allocated memory:
QVector<int> v;
for (int i = 0; i < N; ++i) {
    v.resize(0); // resize(0) preserves capacity, unlike QVector::clear()
    (...)
    v.append(bar);
    (...)
}

Supported containers

QList, QVector and std::vector