Thread: Help with understanding snippet

Hi all.

I am new to C and am trying to get to learn this programming language.

I came across this peice of code and would like anyone of you to explain this to me:

Code:

int main() {
char bbees[10], style[35], buf[35];
int bbb = 16;
int ccc = 0;
sprintf(bbees, "%08x", &bbb);
printf(bbees);
printf("\n");
sprintf(buf, "\\x%c%c\\x%c%c\\x%c%c\\x%c%c", bbees[6],
bbees[7], bbees[4], bbees[5], bbees[2], bbees[3], bbees[0],
bbees[1]);
strcpy(style, buf);
sprintf(buf,"%%08x.%%08x%%n");
strcat(style, buf);
printf("%s\n", style);
printf(style, &bbb, &bbb, &ccc);
}

I would like to know what these lines mean:

sprintf(buf, "\\x%c%c\\x%c%c\\x%c%c\\x%c%c", bbees[6],
bbees[7], bbees[4], bbees[5], bbees[2], bbees[3], bbees[0],
bbees[1]);


sprintf(buf,"%%08x.%%08x%%n");

printf(style, &bbb, &bbb, &ccc);

If anyone can help, I am glad.

THanks you

Originally Posted by narendras

Hi all.

I am new to C and am trying to get to learn this programming language.
I would like to know what these lines mean:

1) Get yourself a good tutorial and/or book and work through them page by page. You'll learn the language... not somebody's idea of a joke.

2) You need to acquire and use the library documentation for your compiler. It's an invaluable resource no programmer should be without. Then you can look this stuff up for yourself.

Originally Posted by quzah

Read the man page: sprintf


Quzah.

Hi quzah,

Thanks for your reply to me. I watched the page you linked me to and learned that sprintf is used to write to a character string. However what I cannot understand is what would this part of the line do:


\\x%c%c\\x%c%c\\x%c%c\\x%c%c"

Are you able to help me to understand this line please?

Thanks you

If you read the sprintf() and/or printf() documentation you should be able to take that apart to figure out what it does...

What does %c do?
what does \\ do?

It's not that hard...

Originally Posted by CommonTater

If you read the sprintf() and/or printf() documentation you should be able to take that apart to figure out what it does...

What does %c do?
what does \\ do?

It's not that hard...

Hi Tater thanks for your message. Is there some documentation somewhere that I can look at? On the link that quzah sent me there is no mention of what those two items do

What i think I learned is that %c means that the output is a character. But i have not learned what \\ does

x	Unsigned hexadecimal integer

\x

Originally Posted by tahmod

x	Unsigned hexadecimal integer

\x

Hi Tahmod, thanks you for your message.

I saw this: FAQ > Format output using printf() (C) - Cprogramming.com there are the formats. However there no is the \\ in the above code. Do you understand if that means something or not?

Originally Posted by MK27

Read the last part of post #8, I edited that in.

Thanks you MK27! That makes good sense

MK27, would the below line:
printf(style, &bbb, &bbb, &ccc);

Output the value of style, and the memory location of bbb, bbb and ccc?

Thanks you

Originally Posted by MK27

Yep, altho you need an actual format string in there first.

I think style is a dynamically-created format string.

Originally Posted by narendras

Hi Tater thanks for your message. Is there some documentation somewhere that I can look at? On the link that quzah sent me there is no mention of what those two items do

What i think I learned is that %c means that the output is a character. But i have not learned what \\ does

1) Yes the link does explain these things... I looked. Next time *actually read* what's there.

2) Any half decent tutorial on C will tell you how to use printf and scanf almost right away... so you should go do some reading.