PushBack Implementation

void PushBack(Vector* v, void* d){
    Eltype T = GetElType(v);
    if (T == INT) PushBackI(v, d);
    else if (T == COMPLEX) PushBackC(v, d);
    else UnknownType();
}

void PushBackI(Vector* v, int* d){
    if (GetCapacity(v) < GetSize(v) + 1) ExpandCapacity(v);
    SetSize(v, GetSize(v) + 1);
    SetElement(v, GetSize(v) - 1, d);
}

void PushBackC(Vector* v, complex* c){
    if (GetCapacity(v) < GetSize(v) + 1) ExpandCapacity(v);
    SetSize(v, GetSize(v) + 1);
    SetElement(v, GetSize(v) - 1, c);
}