CODEWITHSUNDEEP
c++arraysindexingslice
kl0f
kl0f

Reputation: 21

C++ equivalent of Python's : for array indexing

When working with arrays in C++, is there a simple way to access multiple indices of an array at once à la Python's :?

E.g. I have an array x of length 100. If I wanted the first 50 values of this array in Python I could write x[0:50]. In C++ is there an easier way to access this same portion of the array other than x[0,1,2,...,49]?

Upvotes: 2

Views: 1846

Answers (2)

rain city
rain city

Reputation: 217

The closest you can come is probably using iterators. In <algorithm> you can find a bunch of functions that act on an iterator range, for example:

#include <algorithm>

int x[100];
int new_value = 1;
std::fill(std::begin(x), std::begin(x) + 50, new_value);

This would change the values in the range to new_value. Other functions in <algorithm> can copy a range (std::copy), apply a function to elements in a range (std::transform), etc.

If you are using this, be aware that std::begin and std::end only work with arrays, not with pointers! Safer and easier would be to use containers like std::vector.

Upvotes: 1

Maddy
Maddy

Reputation: 774

you can do something like below 

int main()
{
  int myints[]={10,20,30,40,50,60,70};
  array<int,5> mysubints;

  std::copy(myints, myints+5, mysubints.begin());

  for (auto it = mysubints.begin(); it!=mysubints.end(); ++it)
        std::cout << ' ' << *it;

  std::cout << '\n';
}

you can also use vector instead of array data type

Upvotes: 0

Related Questions