Merge pull request #4435 from MugBergerFries/patch-4

Updated C6201

Author: LJSpiller

docs/code-quality/c6201.md

@@ -1,46 +1,48 @@
 ---
-description: "Learn more about: C6201"
-title: C6201
-ms.date: 11/04/2016
+description: "Learn more about: Warning C6201"
+title: Warning C6201
+ms.date: 09/28/2022
 ms.topic: reference
-f1_keywords: ["C6201"]
+f1_keywords: ["C6201", "INDEX_EXCEEDS_MAX", "__WARNING_INDEX_EXCEEDS_MAX"]
 helpviewer_keywords: ["C6201"]
 ms.assetid: eefbbd77-007c-4f28-95f6-6de5ee6a27db
 ---
-# C6201
+# Warning C6201
 
-> warning C6201: buffer overrun for \<variable>, which is possibly stack allocated: index \<name> is out of valid index range \<min> to \<max>
+> Index '*index-name*' is out of valid index range '*minimum*' to '*maximum*' for possibly stack allocated buffer '*variable*'
 
-This warning indicates that an integer offset into the specified stack array exceeds the maximum bounds of that array. This defect might cause random behavior or crashes.
+This warning indicates that an integer offset into the specified stack array exceeds the maximum bounds of that array. It may potentially cause stack overflow errors, random behavior, or crashes.
+
+## Remarks
 
 One common cause of this defect is using an array's size as an index into the array. Because C/C++ array indexing is zero-based, the maximum legal index into an array is one less than the number of array elements.
 
+Code analysis name: INDEX_EXCEEDS_MAX
+
 ## Example
 
-The following code generates this warning because the array index is out of the valid range:
+The following code generates warning C6201. The **`for`** loop condition exceeds the valid index range for `buff` when it sets `i` to 14, which is one element past the end:
 
 ```cpp
-void f( )
+void f()
 {
-  int buff[25];
-  for (int i=0; i <= 25; i++) // i exceeds array bound
-  {
-    buff[i]=0; // initialize i
-    // code ...
-  }
+    int buff[14]; // array of 0..13 elements
+    for (int i = 0; i <= 14; i++) // i == 14 exceeds the bounds
+    {
+        buff[i] = 0; // initialize buffer
+    }
 }
 ```
 
-To correct both warnings, use the correct array size as shown in the following code:
+To correct the warning, make sure the index stays in bounds. The following code shows the corrected loop condition:
 
 ```cpp
-void f( )
+void f()
 {
-  int buff[25];
-  for (int i=0; i < 25; i++)
-  {
-    buff[i]=0; // initialize i
-    // code ...
-  }
+    int buff[14]; // array of 0..13 elements
+    for (int i = 0; i < 14; i++) // i == 13 on the final iteration
+    {
+        buff[i]= 0; // initialize buffer
+    }
 }
 ```