Any example? When you know how everything seems easy, but if you don't well... I know it's a u32 and what the values are but getting it there is another story, at leaset for me. The fact that the 4 bytes need to be in little endian format is another matter but I can deal w/that.
Originally Posted by bobv
To flip between little endian and big endian... simply reverse the assignment order in line 12Code:// IP converter #include <stdio.h> #include <string.h> unsigned long ConvertIP(char *IPString) { union t_cvt { unsigned long ip; unsigned char bv[4]; } cvt; sscanf(IPString,"%hhu.%hhu.%hhu.%hhu",&cvt.bv[0],&cvt.bv[1],&cvt.bv[2],&cvt.bv[3]); // for diagnostic only remove in use printf("%u %u %u %u\n\n",cvt.bv[0],cvt.bv[1],cvt.bv[2],cvt.bv[3]); return cvt.ip; } int main (void) { char ipstr[17]; unsigned int ipaddr; printf("Enter an IP address : "); scanf("%s",ipstr); ipaddr = ConvertIP(ipstr); printf("\n %x\n\n",ipaddr); return 0; }
Last edited by CommonTater; 11-22-2011 at 12:29 PM.
anduril462, Thanks for your reply. I understand your code however this is not the problem I'm trying to solve. I'm trying to pass a string address (pointer) back through a member in the function call. Bob
Yeah, I understood your problem, but gave you an example of passing back values through parameters, so you could extrapolate for your situation. I didn't really want to write your whole solution for you. Note that passing a string (char array) to a function passes a pointer to the first element, so you don't need to do anything else. Treat it like an array in the function. Changing array[3] in the function will change array[3] in the calling code as well:
Code:void parseIP(char *input, char *output) { ... strcpy(output, "foobar"); // this will change the actual string you passed in }
Anduril,
I'm not trying to change the contents of a string or other value. I'm trying to pass back a pointer to the 4th char (&str+4) in the string w/o using the return statement.
Thanks for your time,
Bob
Based Anduril's example in message #16...
Code:void parseIP(char *input, char *output) { // ... output = &input[4]; }
