using a simple assert() macro

Question

I'm new to programming & i found this code when i was going through a book. I believe it gives an example of how to use a defined assert() macro. It doesn't compile on code::blocks 10.05. I get errors such as

'#' is not followed by a macro parameter
unterminated #else
in function 'int main()' 'ASSERT' was not declared in this scope

Code:

#include<iostream>
#define DEBUG

#ifndef DEBUG  
#define ASSERT(x)
#else
#define ASSERT(x)\   
if(!(x))\
{\
       cout<<"Error!!Assert"<<#x<<"failed\n";\
       cout<<"on line"<<__LINE__<<"\n";\
       cout<<"in file"<<__FILE__<<"\n";\
}\
#endif

using namespace std;

int main()
{
    int x = 5;
    cout<<"\nFirst assert.";
    ASSERT(x==5);
    cout<<"\nSecond assert.";
    ASSERT(x!=5);
    cout<<"\nDone."<<endl;

    return 0;
}

Any help would be greatly appreciated. Thanks in advance.

Are you putting an empty line before #define ASSERT(x)\ if(!(x))\ ? Try taking out the empty line if you are. — irrelephant
– irrelephant, Commented Oct 28, 2010 at 1:40
You probably have an empty line after a macro definition line ending with a backslash. You must keep your macro definition lines together, ending each line with a backslash. — Alex Emelianov
– Alex Emelianov, Commented Oct 28, 2010 at 1:40

Anycorn · Accepted Answer · 2010-10-28 01:38:31Z

2

if(!(x))\
{\
       cout<<"Error!!Assert"<<#x<<"failed\n";\
       cout<<"on line"<<__LINE__<<"\n";\
       cout<<"in file"<<__FILE__<<"\n";\
} // no backslash

answered Oct 28, 2010 at 1:38

Anycorn

51.8k45 gold badges173 silver badges267 bronze badges

Sign up to request clarification or add additional context in comments.

6 Comments

AlcubierreDrive Over a year ago

Except surely you mean /*no backslash*/, in case the Original Poster's code has a line like ASSERT(x); DoSomethingImportant(); :-)

UncleBens Over a year ago

I don't see a problem with the comments. What you would have a problem with is usages like: if (x) ASSERT(y) else foobar(z);

AlcubierreDrive Over a year ago

@UncleBens the // would comment out DoSomethingImportant().

UncleBens Over a year ago

@Jon: Doesn't tokenization (including comment removal) occur before macro expansion?

Anycorn Over a year ago

@Uncle there is one compiler i know (nvcc) that goes crazy having '//' in macros. :-(

|

Collectives™ on Stack Overflow

using a simple assert() macro

1 Answer 1

6 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

6 Comments

Your Answer

Sign up or log in

Post as a guest

Related