Help me remember!

[shrubble]

I've got a C++ side-job. It's not MFC or .NET, just straight C++ (really almost just C), and I can't remember some really basic stuff that I know I learned in my second semester of C++. Please to help!

Let's say that, instead of using CStrings (or any string data type), we are using char arrays for string storage:

char myFile[9] = "hello.txt";

(Oh, and we are using the <stdio.h> library for i/o)

and let's also postulate (2-point word!) that we've written a function to take this file name as an argument, but that argument must take the following (pointer) form:

bool fileExists(char *infile)
{
  //... body of function
}

I cannot, for the life of me, remember how to pass the char array ('myFile[9]') into that function, so that the function has a handle on the file.

Anyone in the mood to point out the incredibly obvious?

"I would rather have a free bottle in front of me, than a pre-frontal lobotomy..."

-Shrubble

http://www.ishrubble.com

 

[PerFnurt]

First of all,

char myFile[9] = "hello.txt";

shouldn't compile, since "hello.txt" consists of 10 chars (and if you don't know which char the 10th is, I'd say you should re-take that class)


Secondly, it should be a const parameter

bool fileExists(const char *infile)
{
  //... body of function
}

These things aside, have you tried the obvious?

if(fileExists(myFile)) { // ...

/Per

_{&quot;It was a work of art, flawless, sublime. A triumph equaled only by its monumental failure.&quot;}

 

[shrubble]

Man- I wrote this at 6:30AM, a long way from home and a compiler... take it easy on me for miscounting!

At any rate, thanks for the response.

Why use const for the argument?

"I would rather have a free bottle in front of me, than a pre-frontal lobotomy..."

-Shrubble

http://www.ishrubble.com

 

[Salem]

char myFile[9] = "hello.txt";

Is an error in C++ (the string doesn't fit), but is valid in C (though the result is not a string, there is no \0)

If you want to avoid the counting, then

char myFile[] = "hello.txt";

does exactly what you want it to in both C and C++

If you've no intention of modifying your string, then make it a string constant.

char *myFile = "hello.txt";

--

 

[PerFnurt]

>take it easy on me for miscounting!

Aye, sorry if I sounded a bit harsh, wasn't my intention.
I think fast, type fast, so pretty pleasy with sugar on top....etc...

>Why use const for the argument?

Well, I'd assume a function like fileExist shouldn't modify the file name.

const is a way to prevent unintentional fiddling with the parameters. Its about dealing with errors sooner (compile time) rather than later (runtime)...

A trivial example:

void foo1(char* s)
{
  s[0] = 'A'; 
}

void foo2(const char* s)
{
  s[0] = 'A'; // Compile error
}

...
foo1("This will crash!");
foo2("This won't");

/Per

_{&quot;It was a work of art, flawless, sublime. A triumph equaled only by its monumental failure.&quot;}

 

[shrubble]

Thanks everybody!

"I would rather have a free bottle in front of me, than a pre-frontal lobotomy..."

-Shrubble

http://www.ishrubble.com