Question

C++ programming

write a program that asks a user to enter a random IP number

(IP number is nothing but 4 numbers with dots in between and each number is between 0 and 255)

(example: 1.2.3.4

or

255.255.255.255)

The program you will write (Write the program with string function) checks the entered number for

1) making sure each part is between 0 and 255

(if it's 256 or more, it's going to print a message saying one of the values is too big)

2) each part has maximum 3 digits )

if it's more, it's going to print a message saying too many digits)

3) making sure that the entered number doesn't contain any alphabetic character such as a b c d

if that's the case, it's going to print a message saying only numbers allowed)

4) if the number doesn't have any of the above conditions, then it will print "correct ip number"

Thank you for your help !!!

Answer 1

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
using namespace std;

int validate_ip(char *);

int main() {
char str[15];

cin.getline(str, 15);

validate_ip(str);
return 0;
}
int validate_number(char *str) {
   while (*str) {
      if(!isdigit(*str)){ //if the character is not a number, return false
         
         return 0;
      }
      str++; //point to next character
   }
   return 1;
}
int validate_ip(char *ip) { //check whether the IP is valid or not
   int i, num, dots = 0;
   char *ptr;
   if (ip == NULL)
      return 0;
      ptr = strtok(ip, "."); //cut the string using dot delimiter
      if (ptr == NULL)
         return 0;
   while (ptr) {
      if (!validate_number(ptr)){ //check whether the sub string is holding only number or not
          printf("only numbers allowed");
          return 0;  
      } 
         
         num = atoi(ptr); //convert substring to number
         if (num >= 0 && num <= 255) {
            ptr = strtok(NULL, "."); //cut the next part of the string
            if (ptr != NULL)
               dots++; //increase the dot count
         }
         else if(num>1000) {
               printf("too many digits");
               return 0;
         } 
         else{
               printf("one of the values is too big");
               return 0;
          }
           
    }
    if (dots != 3) //if the number of dots are not 3, return false
       return 0;
    return 1;
}