The size of an array is static in C++. You cannot dynamically resize it. That’s what
std::vector is for:std::vector<int> v; // size of the vector starts at 0
v.push_back(10); // v now has 1 element
v.push_back(20); // v now has 2 elements
v.push_back(30); // v now has 3 elements
v.pop_back(); // removes the 30 and resizes v to 2
v.resize(v.size() - 1); // resizes v to 1
Here is another way to implement without using Vectors in C++:
int size = 10;
int* arr = new int[size];
void resize() {
size_t newSize = size * 2;
int* newArr = new int[newSize];
memcpy( newArr, arr, size * sizeof(int) );
size = newSize;
delete [] arr;
arr = newArr;
}