What data type are you using for your string? Is it the string type or a char*? It also looks like your code to insert is not complete. What happenes if you want to insert into the middle of the array? How do you get the values into the the array after the insert point? I would also suggest making your code to resize the array its own function and make it private in your class. than you just have a call to rersize if the array isnt big enough and the code to insert the element.