error C2106: '=' : left operand must be l-value

Hi,

The following code generates the error:"error C2106: '=' : left operand must be l-value"

Code:

// This is the main project file for VC++ application project 
// generated using an Application Wizard.

#include "stdafx.h"
#include "stdio.h"
#using <mscorlib.dll>
using namespace System;


#define IN 1 /* inside a word */
#define OUT 0 /* outside a word */
/* count lines, words, and characters in input */

main()
{
int c, nl, nw, nc, state;
state = OUT;
nl = nw = nc = 0;
while ((c = getchar()) != EOF) {
++nc;
if (c == '\n')
++nl;
if (c == ' ' || c == '\n' || c = '\t')
state = OUT;
else if (state == OUT) {
state = IN;
++nw;
}
}
printf("%d %d %d\n", nl, nw, nc);
}

Can you tell me what is the reason?
Thanks!!

1: Learn to indent your code properly.
2: Which line is it complaining about, I'm to busy to try to compile it myself.
3: Should this be == instead of =?

Code:

if (c == ' ' || c == '\n' || c = '\t')

using namespace System;
is this C?

you need to indent properly
and show us the line that caused the error
also note that c = '\t' should be c == '\t'

Totally unreadable code. This code will get nowhere. If I'd grate you from A to F, you'd get G.
http://cpwiki.sourceforge.net/User:Elysia/Indentation

If you'd give us the line number where the error occurred maybe we could help more...
Until then there's definitely something wrong here

Code:

if (c == ' ' || c == '\n' || c = '\t')

I'm sure you meant...

Code:

if (c == ' ' || c == '\n' || c == '\t')

I'm not sure if that generated the error, I remember Borland C++ 3.1, which is a very old compiler, used to generate errors like that when assigning values in if statements.

Originally Posted by aLiNuSh

If you'd give us the line number where the error occurred maybe we could help more...
Until then there's definitely something wrong here

Code:

if (c == ' ' || c == '\n' || c = '\t')

I'm sure you meant...

Code:

if (c == ' ' || c == '\n' || c == '\t')

I'm not sure if that generated the error, I remember Borland C++ 3.1, which is a very old compiler, used to generate errors like that when assigning values in if statements.

I'm pretty sure that's the problem. (c == ' ' || c == '\n' || c) is not an lvalue (an lvalue is "something that can be assigned a value", so a simple variable, one cell of an array or a dereferences pointer).

--
Mats

And, anyway . . .

Code:

if (c == ' ' || c == '\n' || c == '\t')

Consider isspace() from <ctype.h>. It does basically just that, except more portably. It also counts vertical tabs ('\v') and carriage returns ('\r') as whitespace in the standard C locale, and whatever else might count as "whitespace" in any other locale the user might be using.

Originally Posted by Elysia

Totally unreadable code. This code will get nowhere. If I'd grate you from A to F, you'd get G.

Then you would not make it far as a grader.

'G' as in Good!

If the grading was based purely on indentation, I can't say it would be very favourable, however . . . .

More like G as in garbage.

Originally Posted by Elysia

More like G as in garbage.

Blah blah blah.

It takes a lot of experience (years) to completely understand the value of indentation. This is why so many beginners have poor indentation. It's not their fault. Telling a beginner "Remember to indent properly" is just about as memorable as telling somebody "Remember to scratch directly behind your left ear before descending the staircase." It might be important, but without some context it isn't going to stick.

You can make all sorts of arguments why indentation is important. The beginner will rightfully say, "So what?" This is because of a lack of experience, not stupidity.

If you want to fail (or, in your case, "worse than fail") introductory students because their indentation sucks, you will find your classes mysteriously empty of students. Nobody wants to learn from a psycho like that.

It amazes me that people even write code with no a single indent at all. How can they even read such code?
Yes, I'm cranky today.

Originally Posted by Elysia

It amazes me that people even write code with no a single indent at all. How can they even read such code?

That question assumes they can read even properly indented code. Most beginners deal with a single line at a time.

Experienced programmers should push the importance of indentation but also remain patient as beginners slowly realize why.

> It takes a lot of experience (years) to completely understand the value of indentation. This is why so many
> beginners have poor indentation. It's not their fault.

I always indented properly, from the beginning. It was obvious to me that it's hard to get the logic right if one doesn't bother to write the code so it's clear which nesting level one is in.

> Nobody wants to learn from a psycho like that.

There are automatic indenting tools available, so even if the student doesn't feel like indenting properly as they go, they can easily take care of it afterwards if they're told how.

Originally Posted by robatino

I always indented properly, from the beginning.

And some people played the piano at age 2.

There are automatic indenting tools available, so even if the student doesn't feel like indenting properly as they go, they can easily take care of it afterwards if they're told how.

Indentation should be taught. I object to the idea of "failing" students for bad indentation at beginning levels. Are we deliberately trying to discourage people from persevering?