IP.c

#include <stdio.h>
#include <string.h>  
/*
Function : extractIpAddress
Arguments : 
1) sourceString - String pointer that contains ip address
2) ipAddress - Target variable short type array pointer that will store ip address octets
*/
void extractIpAddress(unsigned char *sourceString,short *ipAddress)
{     unsigned short len=0;     unsigned char  oct[4]={0},cnt=0,cnt1=0,i,buf[5];       len=strlen(sourceString);     for(i=0;i<len;i++)     {         if(sourceString[i]!='.'){             buf[cnt++] =sourceString[i];         }         if(sourceString[i]=='.' || i==len-1){             buf[cnt]='\0';             cnt=0;             oct[cnt1++]=atoi(buf);         }     }     ipAddress[0]=oct[0];     ipAddress[1]=oct[1];     ipAddress[2]=oct[2];     ipAddress[3]=oct[3];
} 
int main()
{     unsigned char ip[20]={0};     short ipAddress[4];           printf("Enter IP Address (xxx.xxx.xxx.xxx format): ");     scanf("%s",ip);           extractIpAddress(ip,&ipAddress[0]);           printf("\nIp Address: %03d. %03d. %03d. %03d\n",ipAddress[0],ipAddress[1],ipAddress[2],ipAddress[3]);          if(ipAddress[0]>=0 && ipAddress[0]<=127)         printf("Class A Ip Address.\n");     if(ipAddress[0]>127 && ipAddress[0]<191)         printf("Class B Ip Address.\n");     if(ipAddress[0]>191 && ipAddress[0]<224)         printf("Class C Ip Address.\n");     if(ipAddress[0]>224 && ipAddress[0]<=239)         printf("Class D Ip Address.\n");     if(ipAddress[0]>239)         printf("Class E Ip Address.\n");           return 0;
}