How to add element to C++ array?

Question

I want to add an int into an array, but the problem is that I don\'t know what the index is now.

int[] arr = new int[15];
arr[0] = 1;
arr[1] = 2;
arr[2] = 3;         


        

Answer 1

Arrays in C++ cannot change size at runtime. For that purpose, you should use vector instead.

vector arr;
arr.push_back(1);
arr.push_back(2);

// arr.size() will be the number of elements in the vector at the moment.

As mentioned in the comments, vector is defined in vector header and std namespace. To use it, you should:

#include

and also, either use std::vector in your code or add

using std::vector; 

or

using namespace std;

after the #include line.