I'm trying to sort an array of numbers in ascending order and don't know whats wrong with my code (I'm completely new to vectors). I should first copy the input array (data) into an STL vector, then apply STL’s sorting algorithm to the vector, and finally copy the vector back into the array.
void STLSort(int data[],int size)
{
vector<int> a1;
a1.reserve(size);
for(int i=0;i<size;i++)
a1[i]=data[i];
sort(a1.begin(),a1.end());
for(int i=0;i<size;i++)
data[i]=a1[i];
}
Thanks.
You can sort the range directly:
void sort_me(int * arr, unsigned int size)
{
std::sort(arr, arr + size);
}
int main()
{
int a[] = { 3, 11, 7 };
sort_me(a, sizeof(a)/sizeof(int));
// or even just in-place:
int b[] = { 12, -1, 88, 0 };
std::sort(b, b + sizeof(b)/sizeof(int));
}
Even more hip: a template:
template <typename T, unsigned int N>
void sort_me_v2(T (&arr)[N])
{
std::sort(arr, arr + N);
}
int main()
{
int c[] = { -1, 2, -3, 4 };
sort_me_v2(c);
}
a1.reserve(size);
This allocates place for the items, but does not change the size() of the vector. In effect, end() is the same as begin() so you're sorting an empty vector. You should use
a1.resize(size);
sort anyway, if he's lucky.
operator[] isn't required to do bounds checking.reserve.