Validating IP addresses

Author: divyaachoudharyy

Strings/Validate_IP_address.cpp

@@ -0,0 +1,74 @@
+/*************************************************************************
+
+
+Write a program to Validate an IPv4 Address. 
+
+According to Wikipedia, IPv4 addresses are canonically represented in 
+dot-decimal notation, which consists of four decimal numbers, 
+each ranging from 0 to 255, separated by dots, e.g., 172.16.254.1 . 
+
+
+The generalized form of an IPv4 address is (0-255).(0-255).(0-255).(0-255). 
+Here we are considering numbers only from 0 to 255 and 
+any additional leading zeroes will be considered invalid.
+
+Your task is  to complete the function isValid which returns 1, 
+if the ip address is valid else returns 0. 
+
+The function takes a string s as its only argument .
+
+**************************************************************************/
+
+
+SOLUTION (in C++):
+
+#include<bits/stdc++.h>
+
+using namesapce std;
+
+int isValid(string s)
+{
+    s += '.';
+    int countDots = 0;
+    string str = "";
+    for(int i = 0;i<s.length();i++)
+    {
+        if(s[i] != '.')
+        {
+           if(s[i] >= 48 && s[i] <= 57)
+                 str += s[i];
+           else
+                 return 0;
+        }
+        if(s[i] == '.')
+        {
+           if(str[0] == '.' && str.length() > 1)
+              return 0;
+           stringstream obj(str);
+           int x = 0;
+           obj>>x;
+           if(x<0 || x>255)
+               return 0;
+           if(str.size() == 0)
+               return 0;
+           countDots++;
+           str = "";
+    }
+    if(countDots == 4)
+       return 1;
+    else 
+       return 0;
+}
+
+
+int main()
+{
+   string s;
+   cin>>s;
+   int k = isValid(s);
+   if(k == 0)
+     cout<<"Valid"<<endl;
+   else
+     cout<<"Not Valid"<<endl;
+   return 0;
+}