char-question

Hi again.

I want to seperate a QUERY_STRING of my Apache ( so CGI ) with C. It is in the form "arch=foo&status=bar", and I need "foo" in char arch[] and "bar" in char status[] to redirect users to a specific file... . This is what I did:

Code:

int i;
char *seperate_arch(char string[],char outstring[]) {
	int length = strlen(string);
	for(i=4;i<=length;i++) {
		if(string[i] == '&') break;
		outstring[i] = string[i];
	}
global_i = i;
return outstring;
}
char *seperate_status(char string[],char outstring[]) {
	int length = strlen(string);
	for(i=i++;i<=lenght;i++) 
		outstring[i] = string[i];
return oustring;
}
int main(void) {
	char arch[255],status[255];
	strcpy(arch,seperate_arch(getenv("QUERY_STRING"),arch));
strcpy(status,seperate_status(getenv("QUERY_STRING"),status));

(...)
}

arch contains nothing and status a "n" with a "~" ... So whats wrong ?

greets, demonus

Here's one idea.

Code:

int i;
char *seperate_arch(char string[],char outstring[]) {
	int j = 0;
	int length = strlen(string);
	for(i=5;i<length;i++) {
		if(string[i] == '&') break;
		outstring[j++] = string[i];
	}
//global_i = i;
outstring[j] = '\0';
return outstring;
}
char *seperate_status(char string[],char outstring[]) {
	int j = 0;
	int length = strlen(string);
	for(i+=8;i<length;i++) 
		outstring[j++] = string[i];
outstring[j] = '\0';
return outstring;
}

hm. works, thanks a lot. I just wonder *why* it works because of changing one integer ... ( and the '\0' stuff I forgot )

Why not have a more general function such as
char *seperate(char string[],char outstring[], char *name)
You'll find the strstr() function most useful here.

Which you would call with
seperate(getenv("QUERY_STRING"),arch,"arch=");
seperate(getenv("QUERY_STRING"),status,"status=");

> strcpy(arch,seperate_arch(getenv("QUERY_STRING"),a rch));
This is a waste of effort. The separate function returns arch, so all you end up doing is the equivalent of
strcpy( arch, arch );

Originally posted by Salem

This is a waste of effort. The separate function returns arch, so all you end up doing is the equivalent of
strcpy( arch, arch );

Much worse, this is dangerous of one wants ones program to work correctly in different compilers. According to the standard

The strcpy function copies the string pointed to by s2 (including the terminating null character) into the array pointed to by s1. If copying takes place between objects that overlap, the behavior is undefined.