CODEWITHSUNDEEP
c++c++11
Meechew
Meechew

Reputation: 49

Accessing different elements in an array

in for(auto e : elem) I am trying to figure how to access element e-1. while in pre- C++ 11 it would have just been elem[e-1] I am sure that has to be a c++ 11 equivalent.

Upvotes: 0

Views: 75

Answers (2)

Jarod42
Jarod42

Reputation: 217235

With range-v3, you might do

for (auto [p, n] : ranges::view::zip(v, v | ranges::view::drop(1))) {
    // ...
}

Demo

Upvotes: 1

Lukas-T
Lukas-T

Reputation: 11340

Those two do vastly different things:

for(auto e : elem)

is syntactic sugar for a loop the iterates through the whole collection elem, whereas

elem[e - 1]

is accessing a single element of elem at the given index e - 1.

C++11 didn't remove access by index nor is it considered bad practice, because sometimes you don't have any other choice for implementing an algorithm.

Upvotes: 0

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