Reading from a textfile with unknown length?

[c++] Need help with pointers?
Hi I want to make a program that can read data from a text file into memory.

Here is the format of the text file:
Quantity
Brand
Cost

So text file 1 could be:
2
Dodge
15000

And text file 2 could be:
2
Dodge
15000

4
Toyota
6500

I have created a struct called

Code:

struct Car
{
int quantity;
char brand[20];
double cost;
};

Now how I input data into the struct if I don't even know how big the struct array size should be?

In my main I have Car Cars[]; declared but I have left the brackets empty because I don't know what the size it should be.

Please help me with this.

Why use an array if you don't know how many you're going to need? You should look into other containers, such as vector.

No need to use pointers at all.

Create a std::vector<Car>. Open file. Read one Car from the file, and append it to the vector. Repeat (read another Car and append) until whole file read. Close file. Done.

Ah I see. Thank you so much!

Additionally, you shouldn't be using a char array here either; just use std::string for your brand name.