diff --git a/flawfinder b/flawfinder
index 60a2c1a..cee78ee 100755
--- a/flawfinder
+++ b/flawfinder
@@ -1461,6 +1461,7 @@ def process_c_file(f, patch_infos):
     linenumber = 1
     ignoreline = -1
 
+    cpplanguage = f.endswith(".cpp") or f.endswith(".cxx") or f.endswith(".cc")
     incomment = 0
     instring = 0
     linebegin = 1
@@ -1644,9 +1645,12 @@ def process_c_file(f, patch_infos):
                                                      startpos + max_lookahead]
                             hit.hook(hit)
                 elif p_digits.match(c):
-                    while i < len(text) and p_digits.match(
-                            text[i]):  # Process a number.
-                        i += 1
+                    while i < len(text): # Process a number.
+                        # C does not have digit separator
+                        if p_digits.match(text[i]) or (cpplanguage and text[i] == "'"):
+                            i += 1
+                        else:
+                            break
                 # else some other character, which we ignore.
                 # End of loop through text. Wrap up.
     if codeinline: