Copying an array into another array in C++

Question

I have an array created like this:

std::vector<int> data(n);

I have another array b (c Array b[]) having n int values. I want to put these values into data :

for (int i =0 ; i<n, i++) {
    data[i] = b[i]; 
}  

Is there any other method in C++ for copying an array into another arrays ?

Answer 1

It's not entirely clear from your question, but if b and data are both std::vector<int> , then you can do five related things:

Initializing a new data with b

std::vector<int> data = b; // copy constructor

Initializing a new data with b

std::vector<int> data(begin(b), begin(b) + n); // range constructor

Copying b entirely into an existing data (overwriting the current data values)

data = b; // assignment

Copying the first n elements of b into an existing data (overwriting the current data values)

data.assign(begin(b), begin(b) + n); // range assignment

Appending the first n elements of b onto an existing data

data.insert(end(a), begin(b), begin(b) + n); // range insertion

You can also use end(b) instead of begin(b) + n if b has exactly n elements. If b is a C-style array, you can do a using std::begin; and using std::end , and the range construction/assignment/insertion will continue to work.

Answer 2

If b is an int[] (that is, a C array) then you can do:

std::vector<int> data(b + 0, b + n);

If b is also a std::vector then you can just do:

std::vector<int> data = b;

Answer 3

您可以使用copy （但请确保目标向量中有足够的元素！）

copy(begin(b), end(b), begin(data))

Answer 4

std::vector<int> data(b, b + n);