Merge pull request #244 from PulkitKhagta/master

Added code for CaesarCipher in C++

Author: probot-auto-merge[bot]

CaesarCipher/C++/caesarcipher.cpp

@@ -0,0 +1,81 @@
+using namespace std;
+ 
+int main()
+{
+	char message[100], ch;
+	int i, key, n;
+  
+  cout<< "Press 1 to encrypt the message"<<endl;
+  cout<< "Press 2 to decrypt the message" <<endl;
+  
+	cin>>n;
+  if(n == 1)
+    {
+    cout << "Enter a message to encrypt: ";
+    cin.getline(message, 100);
+    cout << "Enter key: ";
+    cin >> key;
+
+    for(i = 0; message[i] != '\0'; ++i){
+      ch = message[i];
+
+      if(ch >= 'a' && ch <= 'z'){
+        ch = ch + key;
+
+        if(ch > 'z'){
+          ch = ch - 'z' + 'a' - 1;
+        }
+
+        message[i] = ch;
+      }
+      else if(ch >= 'A' && ch <= 'Z'){
+        ch = ch + key;
+
+        if(ch > 'Z'){
+          ch = ch - 'Z' + 'A' - 1;
+        }
+
+        message[i] = ch;
+      }
+    }
+
+    cout << "Encrypted message: " << message;
+    }
+  else if(n == 2)
+    {
+    cout << "Enter a message to decrypt: ";
+    cin.getline(message, 100);
+    cout << "Enter key: ";
+    cin >> key;
+
+    for(i = 0; message[i] != '\0'; ++i){
+      ch = message[i];
+
+      if(ch >= 'a' && ch <= 'z'){
+        ch = ch - key;
+
+        if(ch < 'a'){
+          ch = ch + 'z' - 'a' + 1;
+        }
+
+        message[i] = ch;
+      }
+      else if(ch >= 'A' && ch <= 'Z'){
+        ch = ch - key;
+
+        if(ch > 'a'){
+          ch = ch + 'Z' - 'A' + 1;
+        }
+
+        message[i] = ch;
+      }
+    }
+
+    cout << "Decrypted message: " << message;
+    }
+  else
+    {
+    cout<< "Entered number neither 1 nor 2"<<endl;
+    }
+	return 0;
+}