Question

First, review your C language data types Learn how to use the strtok() function in C language. There are plenty of examples on the Internet. Use this function to parse both an example IP address, eg. 192.168.1.15, into four different strings. Next use the atoi() function to convert these into four unsigned char's. (Hint: you will need to typecast, eg unsigned char X-(unsigned char)atoi("234"); Now, if you view a 32 bit number in base 256, the right most column would be the 1's (256 to the zero power), the next column to the right would be the 256's column (256 to the first power) and so on. So if you think it through, you could build the correct 32bit number (pick the right data type, unsigned of course) from the four 8 bit numbers and the powers of 256. Or, if you are really clever, you could use bit-shifts and some addition Develop these steps into a function with a string as an argument so you could convert any IP address or netmask into a 32 bit number. Finally, use a bitwise AND operation with any IP and netmask to yield the network value, and display this value. Submit this code here.

Answer 1

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
union iptolint
{
char ip[16];
unsigned long int n;
};
unsigned long int conv(char []);

main()
{
union iptolint ipl;
printf(" Enter the IP Address to be converted :\n");
scanf("%s",ipl.ip);
ipl.n=conv(ipl.ip);
printf(" Equivalent 32-bit long int is : %lu\n",ipl.n);
union iptolint mask;
printf(" Enter the Mask to be converted :\n");
scanf("%s",mask.ip);
  
//now performing and
long int m = ipl.n & mask.n;
printf("Result :%ld\n",m);
}

unsigned long int conv(char ipadr[])
{
unsigned long int num=0,val;
char *tok,*ptr;
tok=strtok(ipadr,".");
while( tok != NULL)
{
val=strtoul(tok,&ptr,0);
num=(num << 8) + val;
tok=strtok(NULL,".");
}
return(num);
}