docs: update readme

README.md

@@ -64,7 +64,7 @@ In **encode mode**:
 
 In both modes:
 
-- Type `exit` to quit the program
+- Press `Ctrl+D` to quit the program
 
 ## Examples
 

main.cpp

@@ -25,22 +25,15 @@ const map<char, string> morse_map = {
 
 bool should_exit = false;
 
-bool is_exit(const string &s) {
-  return s.length() == 4 && tolower(static_cast<unsigned char>(s[0])) == 'e' &&
-         tolower(static_cast<unsigned char>(s[1])) == 'x' &&
-         tolower(static_cast<unsigned char>(s[2])) == 'i' &&
-         tolower(static_cast<unsigned char>(s[3])) == 't';
-}
-
 string read_input(const string &prompt) {
   cout << prompt;
   string line;
-  if (!getline(cin, line) || line.empty())
-    return "";
-  if (is_exit(line)) {
+  if (!getline(cin, line)) {
     should_exit = true;
     return "";
   }
+  if (line.empty())
+    return "";
   return line;
 }
 
@@ -119,7 +112,7 @@ public:
 void decode_mode() {
   MorseDecoder decoder;
   cout << "Decode mode: Enter morse sequence to decode. Press 'e' to switch to "
-          "encode mode, 'exit' to exit.\n\n";
+          "encode mode.\n\n";
 
   while (!should_exit) {
     string input = read_input("Enter morse sequence: ");
@@ -171,7 +164,7 @@ void decode_mode() {
 void encode_mode() {
   MorseEncoder encoder;
   cout << "Encode mode: Enter text to see Morse code patterns. Press 'd' to "
-          "switch to decode mode, 'exit' to exit.\n\n";
+          "switch to decode mode.\n\n";
 
   while (!should_exit) {
     string input = read_input("Enter text to encode: ");