# V6025\. Possibly index is out of bound\.

When indexing into a variable of type 'array', 'list', or 'string', an 'IndexOutOfBoundsException' exception may be thrown if the index value is outbound the valid range\. The analyzer can detect some of such errors\.

For example, it may happen when iterating through an array in a loop:

```cpp
int[] buff = new int[25];
for (int i = 0; i <= 25; i++)
  buff[i] = 10;
```

Keep in mind that the first item's index is 0 and the last item's index is the array size minus one\. Fixed code:

```cpp
int[] buff = new int[25];
for (int i = 0; i < 25; i++)
  buff[i] = 10;
```

Errors like that are found not only in loops but in conditions with incorrect index checks as well:

```cpp
void ProcessOperandTypes(int opCodeValue, byte operandType)
{
  byte[] OneByteOperandTypes = new byte[0xff];
  if (opCodeValue < 0x100)
  {
    OneByteOperandTypes[opCodeValue] = operandType;
  }
  ...
}
```

Fixed version:

```cpp
void ProcessOperandTypes(int opCodeValue, byte operandType)
{
  byte[] OneByteOperandTypes = new byte[0xff];
  if (opCodeValue < 0xff)
  {
    OneByteOperandTypes[opCodeValue] = operandType;
  }
  ...
}
```

Programmers also make mistakes of this type when accessing a particular item of an array or list\.

```cpp
private Map<String, String> TransformListToMap(List<String> config)
{
  Map<String, String> map = new HashMap<>();
  if (config.size() == 10)
  {
    map.put("Base State", config.get(0));
    ...
    map.put("Sorted Descending Header Style", config.get(10));
  }
  ...
  return map;
}
```

In this example, the programmer made a mistake in the number of entries in the 'config' list\. The fixed version should look like this:

```cpp
private Map<String, String> TransformListToMap(List<String> config)
{
  Map<String, String> map = new HashMap<>();
  if (config.size() == 11)
  {
    map.put("Base State", config.get(0));
    ...
    map.put("Sorted Descending Header Style", config.get(10));
  }
  ...
  return map;
}
```