cpp code for day 2 and 3 (#87)

Author: profgrammer

Day2/C++/profgrammer_reversepalindrome.cpp

@@ -0,0 +1,38 @@
+/*
+  *@author: profgrammer
+  *@date: 30-12-2018
+*/
+
+#include <bits/stdc++.h>
+using namespace std;
+
+
+int main() {
+  string s;
+  cin>>s;
+
+  // method 1: print the string in reverse order
+  cout<<"The reversed string is: ";
+  for(int i = s.size()-1;i >= 0;i--) cout<<s[i];
+  cout<<endl;
+
+  // method 2: swap characters at either end
+  string s1 = s;
+  for(int i = 0, j = s1.size()-1;i <= j;i++, j--){
+    char temp = s1[i];
+    s1[i] = s1[j];
+    s1[j] = temp;
+  }
+  cout<<"The reversed string is: "<<s1<<endl;
+
+  // method 3: library functions
+  s1 = s;
+  reverse(s1.begin(), s1.end());
+  cout<<"The reversed string is: "<<s1<<endl;
+
+  // to check if the string is a palindrome, we need to check if it is equal to its reverse. 
+
+  if(s.compare(s1) == 0) cout<<"The string is a palindrome"<<endl;
+  else cout<<"The string is not a palindrome\n";
+
+}

Day2/README.md

@@ -255,6 +255,47 @@ return 0;
 }
 ```
 
+###[Solution by @profgrammer](./C++/profgrammer_reversepalindrome.cpp)
+```c
+/*
+  *@author: profgrammer
+  *@date: 30-12-2018
+*/
+
+#include <bits/stdc++.h>
+using namespace std;
+
+
+int main() {
+  string s;
+  cin>>s;
+
+  // method 1: print the string in reverse order
+  cout<<"The reversed string is: ";
+  for(int i = s.size()-1;i >= 0;i--) cout<<s[i];
+  cout<<endl;
+
+  // method 2: swap characters at either end
+  string s1 = s;
+  for(int i = 0, j = s1.size()-1;i <= j;i++, j--){
+    char temp = s1[i];
+    s1[i] = s1[j];
+    s1[j] = temp;
+  }
+  cout<<"The reversed string is: "<<s1<<endl;
+
+  // method 3: library functions
+  s1 = s;
+  reverse(s1.begin(), s1.end());
+  cout<<"The reversed string is: "<<s1<<endl;
+
+  // to check if the string is a palindrome, we need to check if it is equal to its reverse. 
+
+  if(s.compare(s1) == 0) cout<<"The string is a palindrome"<<endl;
+  else cout<<"The string is not a palindrome\n";
+}
+```
+
 ### [Solution by @divyakhetan](./C++/reverseday2.cpp)
 
 ```cpp

Day3/C++/profgrammer_hammingdistance.cpp

@@ -0,0 +1,25 @@
+/*
+  *@author: profgrammer
+  *@date: 30-12-2018
+*/
+
+
+#include <bits/stdc++.h>
+using namespace std;
+
+int main() {
+  string s1, s2;
+  cin>>s1>>s2;
+  cout<<"The hamming distance is : ";
+  // the hamming distance is calculated for strings of EQUAL length. hence if the lengths differ we return -1 as an invalid case.
+  if(s1.size() != s2.size()) cout<<-1<<endl;
+  else{
+    // iterate through both strings and find the number of indices where the strings differ. the total of these indices is the hamming distance
+    int hammingDistance = 0;
+    for(int i = 0;i < s1.size();i++){
+      if(s1[i] != s2[i]) hammingDistance++;
+    }
+    cout<<hammingDistance<<endl;
+  }
+
+}

Day3/README.md

@@ -173,6 +173,34 @@ int main(){
 }
 ```
 
+###[Solution by @profgrammer](./C++/profgrammer_hammingdistance.cpp)
+```c
+/*
+  *@author: profgrammer
+  *@date: 30-12-2018
+*/
+
+
+#include <bits/stdc++.h>
+using namespace std;
+
+int main() {
+  string s1, s2;
+  cin>>s1>>s2;
+  cout<<"The hamming distance is : ";
+  // the hamming distance is calculated for strings of EQUAL length. hence if the lengths differ we return -1 as an invalid case.
+  if(s1.size() != s2.size()) cout<<-1<<endl;
+  else{
+    // iterate through both strings and find the number of indices where the strings differ. the total of these indices is the hamming distance
+    int hammingDistance = 0;
+    for(int i = 0;i < s1.size();i++){
+      if(s1[i] != s2[i]) hammingDistance++;
+    }
+    cout<<hammingDistance<<endl;
+  }
+}
+```
+
 ### [hamingDistance](./C++/hammingDistanceday3.cpp)
 
 ```cpp
@@ -199,7 +227,6 @@ int main(){
 	}
 	return 0;
 }
-```
 
 ## C Implementation