CODEWITHSUNDEEP
c++c++11
pyCthon
pyCthon

Reputation: 12341

initialize a vector to zeros C++/C++11

I know in C++11 they added the feature to initialize a variable to zero as such 

double number = {}; // number = 0
int data{};  // data = 0

Is there a similar way to initialize a std::vector of a fixed length to all zero's?

Upvotes: 190

Views: 435639

Answers (4)

a random guy
a random guy

Reputation: 1

For c++: Let's say that the vector has a maximum of 100 int elements. You can initialize it this way:

int vector[100]={0};

Upvotes: -9

Pavan Chandaka
Pavan Chandaka

Reputation: 12741

With recent versions of c++ you can go with std::fill.

I noticed someone mentioned it as comment. But should be an answer and encourage to use standard library algorithms which are mentioned by experts, very well tested and proven.

    std::vector<int> vecOfInts;
    vecOfInts.resize(10);

    std::fill(vecOfInts.begin(), vecOfInts.end(), 0);

    for (auto const& intVal : vecOfInts)
    {
        std::cout << intVal << " ";
    }

Upvotes: 4

Peter
Peter

Reputation: 1275

Initializing a vector having struct, class or Union can be done this way

std::vector<SomeStruct> someStructVect(length);
memset(someStructVect.data(), 0, sizeof(SomeStruct)*length);

Upvotes: 4

ronag
ronag

Reputation: 51255

You don't need initialization lists for that:

std::vector<int> vector1(length, 0);
std::vector<double> vector2(length, 0.0);

Upvotes: 358

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