Thread: Please check my work...

You have 3 correct. The first answer is false, because while they may default to automatic types, you can change that with the 'static' keyword.

[edit]
As we all know, if part of the answer is false, the whole thing is false. However, you'll probably get it wrong if you say it's false, due to the horrible wording of most all of these questions.
[/edit]

Quzah.

Either way you're failing, so it doesn't really matter if it's 5 or 3.


Quzah.

Here's an idea. Take them each one at a time, and with the question, write a small paragraph on why you think each one is the way you answered it. Then we can see where your logic is off, and it won't simply be a case of us giving you the right answers. This why you'll have to think about each question.

Originally Posted by viciousv322

Code:

2.	The statement   for(;5;)  is an easy way to make a
loop execute only five times.      T

initialization; condition; increment

Your condition will never evaluate to false. It is like creating the infinite loop like:

Code:

while( 1 )
    ...do forever...

Since the condition always evaluates to true, (anything non-zero is true), this loop will never end.

Originally Posted by viciousv322

Code:

3.	The while and for statements are virtually identical
so that either can be used in place of the other with slight
modification to the code.  F

From what i've written, its taken more than slight modification... but what may be slight to someone seems like a lot to me.

The changes are slight. It boils down to moving the incrementation and initialization around. Very minor changes in the grand scheme of things.

Originally Posted by viciousv322

Code:

4.	The extern keyword is needed to reference a
piece of data defined in another source file.  T

After rereading this question...i don't know if it is "needed" but the defintion i got was "The variable or function may be defined in another source file, or later in the same file. Declarations of variables and functions at file scope are external by default"

To make a variable in one file visible in another, you reference it via 'extern'. So yes, it's needed.

Originally Posted by viciousv322

Code:

5.	It is required that macro names be in upper case.  F

After further research, this may be True...However, i could only find sources where they said that it is "good programming" but i could not find a source that says it is required?

No, it's not needed. The standard doesn't say you have to make your macros upper case. It's commonly done to denote that you are in fact using a macro, but it's not a requirement of the language.

[edit]
automatic variables are created at the beginning of the scope block they're defined in. They are not initialized upon creation. They are destroyed at the end of scope. You should not attempt to access them after they have gone out of scope, as they are destroyed and retain no value.

static variables are created at the start of the program. They are initialized to zero at the time they are created. They only are destroyed at the end of the program. Their values are maintained even when their scope has ended.

I'm sure someone else will have a few words to say, but that's the basics of it.
[/edit]

Quzah.

Originally Posted by viciousv322

Code:

6.	The NULL byte is automatically placed at the end of all arrays.  T

I was under the impression that null bytes were used to end strings of arrays, not sure if its ALL arrays...or if its automatic for that matter...

The null character is only used for character arrays which are to be used as strings. A string is zero or more characters followed by a null character. That's the only time a null character is used. You can initialize character arrays at creation time, or use string literals with pointers, and they'll automatically get a null character in this case. But not all arrays get them. Why would an array of doubles need a null character on the end?

Originally Posted by viciousv322

Code:

7.	Arithmetic expressions in a macro should be surrounded
by parentheses, even if that means enclosing the entire macro body.   F

I thought the parenthesis was only used to declare the order of the operations, but not needed for regular/ simple math such as 2+2. Are parenthesis required around the entire operation?

Consider the following:

Code:

#define MULT(x,y) x * y

Should be a simple multiplication macro, right? Pass it a few arguments, have it multiply them. What happens when I do this:

Code:

x = MULT( 2 + 3, 5 + 7 );

What is x? Expand the macro:

Code:

x = 2 + 3 * 5 + 7;

Not what you had in mind eh?

Originally Posted by viciousv322

Code:

8.	The  return  statement must always be used when leaving a function.   T

i thought this was a gimme question... am i overlooking/misunderstanding something?

What about a void function?

Code:

void foo( void )
{
    ...do stuff...
    return; /* <-- not needed */
}

Originally Posted by viciousv322

Code:

9.	The keyword  return()  can be used to return as many
data items as you like from a function to the calling program.   T

not sure as i couldn't find a good source

You can only ever return one object at a time in a function. You can have multiple return points, but each one still can only return one thing.

Originally Posted by viciousv322

Code:

10.	Creating an array of 5 integers means that the largest subscript
(also called index) that you can use is 4.  T

Arrays start at 0 so that would be 0,1,2,3,4 for the five integers?

This is poorly worded. Yes, you probably have it right. It depends really on their definition of use. Use as a point of reference? Then you'd be wrong. You are allowed to reference 1 past the end of the array. That is to say:

Code:

int array[5];
...
if( ptr < array+5 ) /* make sure we haven't reached the end of the array... */

That is a legal check. So, there I'm "using" in effect array[5]. However, if they mean use in the sense that you can actually check what value is stored there, and store something there, then you were right in saying true, that all you get is 0 ... 4.

It's really dependant on how pedantic your teacher is. However, reading the wording, and the fact that you don't know most of these answers, I'm going to say your teacher is an idiot, or you just weren't paying attention. I'll assume for the sake of argument that you have been paying attention, and your teacher is lousy. In which case, I'd say "true" to this question.

Quzah.