CODEWITHSUNDEEP
c++c++11vectorsyntax
AK_
AK_

Reputation: 2079

How to initialize a vector<int> v(1000) with values {1,1,1,...,1} without a loop in C++?

We can initialize a vector in C++11 in the following way

vector<int> v {1,2,3,4,5,6}

But what if I want to initialize a vector<int> v(1000) with values {1,1,1,1....1}?

In python it would be:

somelist [1] * 1000

I'm not sure if Python has a loop behind that line but my goal by omitting the loop is to do better in terms of performance and a simpler code.

Upvotes: 2

Views: 2753

Answers (1)

juanchopanza
juanchopanza

Reputation: 227618

If you want a vector of 1000 elements, all set to 1, then std::vector has a constructor that does that for you:

vector<int> v(1000, 1);

The time complexity of this constructor is necessarily linear, but you can expect it to be very fast. You would be hard pressed to find a faster alternative, so if this is an issue, you might require a re-design.

Upvotes: 9

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