How to expand an array dynamically in C++? {like in vector }

Question

Lets say, i have

int *p;
p = new int[5];
for(int i=0;i<5;i++)
   *(p+i)=i;

Now I want to add a 6th element to the array. How do I do it?

Answer 1

You have to reallocate the array and copy the data:

int *p;
p = new int[5];
for(int i=0;i<5;i++)
   *(p+i)=i;

// realloc
int* temp = new int[6];
std::copy(p, p + 5, temp); // Suggested by comments from Nick and Bojan
delete [] p;
p = temp;