C parsing

CM_2020 · 07-05-2008, 12:06 PM

So, here's what I'm wondering if you guys can help me with: I'm fairly new to coding C and I might just be missing a function, so if so this should be easy.

Here's the problem, or, at least, what I need my program to do.
User enters a string, optionally containing a symbol. So, like, "$." I need my program to parse out the string that directly follows it (excluding whitespace) and store it in a char.

So, if "user" entered "hello, my name is $bob what is yours?", the program would return "bob" to a character.

If this post is redundant, I apologize- I looked and didn't find anything similar.

I would greatly appreciate any help.

MacGyver · 07-05-2008, 12:24 PM

First step in finding the '$' is using strchr(). The next step depends upon what you want the program to do. You could manually search through the rest of the string char by char until you find a character to stop at. Finally, after knowing the start and end of the substring, you could strcpy() it to a new malloc()'ed buffer and do whatever you want with it (remembering to free() the buffer later on).

audinue · 07-05-2008, 01:07 PM

Try to learn advance topics: Automata, is a good way to parse something.

CM_2020 · 07-08-2008, 01:52 AM

Quote:

Originally Posted by MacGyver

First step in finding the '$' is using strchr(). The next step depends upon what you want the program to do. You could manually search through the rest of the string char by char until you find a character to stop at. Finally, after knowing the start and end of the substring, you could strcpy() it to a new malloc()'ed buffer and do whatever you want with it (remembering to free() the buffer later on).

Well, what I need it to do is automatically pick out the string that follows the symbol I am searching for.

Now.... I think I may have something here, and I was wondering if you guys could help me a little further? What my newest idea is was to use strtok() to split up input into a series of tokens using the ' ' character. Sooo... "hello, my name is $bob what is yours" would be split up into each of the individual words. However, in what way can I later search each individual token for the "$" character? Also, if I am going about this in the completely wrong way, please- someone tell me?

audinue · 07-08-2008, 02:17 AM

Traditional parsing example:

Code:

char c;

while((c = getchar()) != EOF)
{
    if(c == '$')
    {
        while(isalpha(c = getchar()))
        {
            putchar(c);
        }

        putchar('\n');
    }
}

Input:

Code:

hello my name is $bob what is yours? hi! my name is $angela, nice to meet you

Output:

Code:

bob
angela

Is this help?

CM_2020 · 07-08-2008, 10:33 AM

Yep. Thanks.

07-05-2008, 12:06 PM	#1
CM_2020 Registered User Join Date: Jul 2008 Posts: 3	C parsing So, here's what I'm wondering if you guys can help me with: I'm fairly new to coding C and I might just be missing a function, so if so this should be easy. Here's the problem, or, at least, what I need my program to do. User enters a string, optionally containing a symbol. So, like, "$." I need my program to parse out the string that directly follows it (excluding whitespace) and store it in a char. So, if "user" entered "hello, my name is $bob what is yours?", the program would return "bob" to a character. If this post is redundant, I apologize- I looked and didn't find anything similar. I would greatly appreciate any help.
CM_2020 is offline

07-05-2008, 12:24 PM	#2
MacGyver Deathray Engineer Join Date: Mar 2007 Posts: 3,211	First step in finding the '$' is using strchr(). The next step depends upon what you want the program to do. You could manually search through the rest of the string char by char until you find a character to stop at. Finally, after knowing the start and end of the substring, you could strcpy() it to a new malloc()'ed buffer and do whatever you want with it (remembering to free() the buffer later on). __________________
MacGyver is offline

07-05-2008, 01:07 PM	#3
audinue Ugly C Lover Join Date: Jun 2008 Location: Indonesia Posts: 462	Try to learn advance topics: Automata, is a good way to parse something.
audinue is offline

07-08-2008, 10:33 AM	#6
CM_2020 Registered User Join Date: Jul 2008 Posts: 3	Yep. Thanks.
CM_2020 is offline

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