Need Training Material.....

Hi,
Could any explain the below code.

Code:

---

#include<stdio.h>
#include<string.h>

#define f(a,b) a##b

int main()
{
      printf("%d\n",f(1,2));
}

---

The output of the above code is 12, but if I try as below it gives error why is it so, and if any know about the tutorial on such things please let me know

Code:

---

#include<stdio.h>
int main()
{
        printf("%d\n", 1##2);
}

---

## is only meaningful in macros.


The C preprocessor is not part of the C compiler. The C compiler itself understands very few uses of #.

http://vergil.chemistry.gatech.edu/r...al/basic2.html
Skim down to "The C Preprocessor :: Overview"

Quote:

---

Originally Posted by enggabhinandan

Hi,
Could any explain the below code.

Code:

---

#include<stdio.h>
#include<string.h>

#define f(a,b) a##b

int main()
{
      printf("%d\n",f(1,2));
}

---

The output of the above code is 12, but if I try as below it gives error why is it so, and if any know about the tutorial on such things please let me know

Code:

---

#include<stdio.h>
int main()
{
        printf("%d\n", 1##2);
}

---

---

Hey below is the link which i found bit useful to understand MACROS...


http://gcc.gnu.org/onlinedocs/cpp/Macros.html#Macros

Perhaps you would benefit from a more organised approach to learning C (say a book), or maybe
http://www.eskimo.com/~scs/cclass/notes/top.html

Searching the web for random stuff then posting the results here isn't going to teach you much at all in the long run.