Basic buffered ifstream read

[treefitty]

Hello,

I'm using ifstream and the >> operator to read data from a TXT. The goal is to read in 15 chars (together, NOT separated by spaces) into a "char temp_buffer[16]". After reading it in, I immediately set temp_buffer's index [15] to 0, to insert a null terminator, so that it can be safely cout'ed without continuing to cout garbage.

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Secondary question: Setting aforementioned buffer's index [15] to 0 is necessary, correct? Because, if for example, I make a char Hey[3] in main, where [0] is 'H', [1] is 'e', and [2] is 'y', and if I "cout << Hey;", it will cout garbage afterward, like "Hey*#&$**||||||||||@*#$*@||||:2".
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So, my question about the reading from the TXT file into a buffer is that -- it works -- but only if the characters being read in are 15 or less. If there are 16 or more letters, I get a "stack around temp_buffer corrupted", since it's trying to shove more than it can hold into the buffer. That's the idea of my buffer though: I want it to only STORE as much as it can hold!

void LoadActor(void)
{
	ifstream LOADFILE;
	LOADFILE.open("ACTOR1.txt", ios::in);

	if(LOADFILE.is_open() == true)
	{
		// Some temporary variables to attempt loading into
		char temp_actor_name[16];
		char temp_actor_type[16];
		temp_actor_name[0] = 0;
		temp_actor_type[0] = 0;
		int temp_tile_sheet_id = -1;
		int temp_tile_value_id = -1;

		LOADFILE >> temp_actor_name;//PROBLEM IS HERE (I assume)
		LOADFILE >> temp_actor_type;//PROBLEM IS HERE (I assume)
		LOADFILE >> temp_tile_sheet_id;
		LOADFILE >> temp_tile_value_id;

		LOADFILE.close();

		// Set last (16th) character to null
		temp_actor_name[15] = 0;
		temp_actor_type[15] = 0;
	}
}

In my TXT file:
(example of TXT file that DOES load)

John
Sandwich
44
2

(example of TXT file that CORRUPTS stack)
(because the first field is greater than or equal to 16 chars long)

Electro_Magnetic
Eggs
13
9

Of course, in this code, nothing is happening when data is read into the buffers, but first I want to understand how to avoid corrupting the stack around the buffer.

Thank you for any advice!

[Zhuge]

When you just use the >> operator, you don't it any idea how long the array is. I believe you can use the width() method of cin to say how many characters it should read before stopping.

[treefitty]

Thank you!

It appears I also needed to add an Ignore line per read as well, or else, when it gets around to reading the second char array, it messed with the first one. Weird.

Here is the working code. (Where nothing actually happens with the data, but it is loaded properly into the buffers.)

Also, it appears that "width()" automatically null terminates, so, if I say width(16), it only reads 15, and seems to automatically put a 0 for 16, which is exactly what I wanted anyway.

void LoadActor(void)
{
	ifstream LOADFILE;
	LOADFILE.open("ACTOR1.txt", ios::in);

	if(LOADFILE.is_open() == true)
	{
		// Some temporary variables to attempt loading into
		char temp_actor_name[16];
		char temp_actor_type[16];
		temp_actor_name[0] = 0;
		temp_actor_type[0] = 0;
		int temp_tile_sheet_id = -1;
		int temp_tile_value_id = -1;

		// Read a char array (15 characters with 0 terminator at end)
		LOADFILE.width(16);
		LOADFILE >> temp_actor_name;
		LOADFILE.ignore(INT_MAX, '\n');
		// Read a char array (15 characters with 0 terminator at end)
		LOADFILE.width(16);
		LOADFILE >> temp_actor_type;
		LOADFILE.ignore(INT_MAX, '\n');

		// Read ints
		LOADFILE >> temp_tile_sheet_id;
		LOADFILE >> temp_tile_value_id;

		LOADFILE.close();
	}
}

If anyone sees anything else that looks like it could cause problems or is incorrect/dumb, I'd very much appreciate it being pointed out, thank you