Index: llvm/docs/tutorial/MyFirstLanguageFrontend/LangImpl01.rst
===================================================================
--- llvm/docs/tutorial/MyFirstLanguageFrontend/LangImpl01.rst
+++ llvm/docs/tutorial/MyFirstLanguageFrontend/LangImpl01.rst
@@ -138,9 +138,16 @@
 
       if (isdigit(LastChar) || LastChar == '.') {   // Number: [0-9.]+
         std::string NumStr;
+        int count=0;/*Counts number of '.'. If it is greater than 1 should return error. For example if we have the input as “1.23.45.67”, it should return an error since this is invalid*/
         do {
           NumStr += LastChar;
           LastChar = getchar();
+          if(LastChar == '.'){
+            count++;
+          }
+          if(count>1){
+            return LogError("Invalid number");
+          }
         } while (isdigit(LastChar) || LastChar == '.');
 
         NumVal = strtod(NumStr.c_str(), 0);
@@ -149,10 +156,7 @@
 
 This is all pretty straightforward code for processing input. When
 reading a numeric value from input, we use the C ``strtod`` function to
-convert it to a numeric value that we store in ``NumVal``. Note that
-this isn't doing sufficient error checking: it will incorrectly read
-"1.23.45.67" and handle it as if you typed in "1.23". Feel free to
-extend it!  Next we handle comments:
+convert it to a numeric value that we store in ``NumVal``.Next we handle comments:
 
 .. code-block:: c++
 
Index: llvm/examples/Kaleidoscope/Chapter2/toy.cpp
===================================================================
--- llvm/examples/Kaleidoscope/Chapter2/toy.cpp
+++ llvm/examples/Kaleidoscope/Chapter2/toy.cpp
@@ -48,14 +48,21 @@
     return tok_identifier;
   }
 
-  if (isdigit(LastChar) || LastChar == '.') { // Number: [0-9.]+
+  if (isdigit(LastChar) || LastChar == '.') {   // Number: [0-9.]+
     std::string NumStr;
+    int count=0; // Counts number of '.'. If it is greater than 1 should return false. For example if we have the input as “1.23.45.67”, it should return an error since this is invalid
     do {
       NumStr += LastChar;
       LastChar = getchar();
+      if(LastChar == '.') {
+        count++;
+      }
+      if(count > 1) {
+        return LogError("Invalid number");;
+      }
     } while (isdigit(LastChar) || LastChar == '.');
 
-    NumVal = strtod(NumStr.c_str(), nullptr);
+    NumVal = strtod(NumStr.c_str(), 0);
     return tok_number;
   }