Storing some values from a string to som

Storing some values from a string to some chars

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

unsigned char content[20] = "ip1=10&ip2=10&ip3=4&ip4=210";

unsigned char ip_addr[4] = { 0,0,0,0};

Hello all,

I want the value from my content array after the = and before the & for each of the 4 ip numbers stored in ip_addr[4]. The problem is, the numbers are variable in length.

Last edited on

coder777 (8450)

hello jimclermonts,

use strchr() to find '=' and '&' then you can isolate the number (and convert it is necessary)

The example how to use strchr

/* STRCHR.C: This program illustrates searching for a character
 * with strchr (search forward).
 */

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

int  ch = 'r';

char string[] = "The quick brown dog jumps over the lazy fox";
char fmt1[] =   "         1         2         3         4         5";
char fmt2[] =   "12345678901234567890123456789012345678901234567890";

void main( void )
{
   char *pdest;
   int result;

   printf( "String to be searched: \n\t\t%s\n", string );
   printf( "\t\t%s\n\t\t%s\n\n", fmt1, fmt2 );
   printf( "Search char:\t%c\n", ch );

   /* Search forward. */
   pdest = strchr( string, ch );
   result = pdest - string + 1;
   if( pdest != NULL )
      printf( "Result:\tfirst %c found at position %d\n\n", 
              ch, result );
   else
      printf( "Result:\t%c not found\n" );

   /* Search backward. */
   pdest = strrchr( string, ch );
   result = pdest - string + 1;
   if( pdest != NULL )
      printf( "Result:\tlast %c found at position %d\n\n", ch, result );
   else
      printf( "Result:\t%c not found\n" );
}

naivnomore (43)

#include <iostream>
#include <string>
#include <sstream>
#include <iterator>
using namespace std;

int main()
{
	unsigned char content[] = "ip1=10&ip2=10&ip3=4&ip4=210";
	unsigned char ip_addr[4] = { 0,0,0,0};

	stringstream ssip;
	string sc = (const char *)content;
	string::size_type fpos1 = sc.find('='), fpos2;
	while (fpos1 != string::npos){
		fpos2 = sc.find('&', fpos1);
		if (fpos2 != string::npos)
			ssip << sc.substr(fpos1 + 1, fpos2 - fpos1 - 1) << " ";
		else
			ssip << sc.substr(fpos1 + 1);
		fpos1 = sc.find('=', fpos2);
	}

	size_t i = 0;
	int ip;
	while (ssip >> ip)
		ip_addr[i++] = ip;

	//Display ip_addr array
	copy(ip_addr, ip_addr+4, ostream_iterator<int>(cout, ":"));
}

Storing some values from a string to some chars

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