# V2522\. MISRA\. The 'switch' statement should have 'default' as the last label\.

This diagnostic rule is based on the software development guidelines developed by [MISRA](https://www.misra.org.uk/) \(Motor Industry Software Reliability Association\)\.

This diagnostic rule is relevant only to C\+\+ programs\. A 'switch' statement should have 'default' as the last label\.

Adding a 'default' label at the end of every 'switch' statement makes the code clearer and guarantees that any possible case where none of the labels matches the value of the control variable will be handled\. Since such situations have to be dealt with somehow, every 'default' label should contain \(in addition to 'break' or 'throw'\) an expression or comment explaining why no actions are carried out\. 

Example 1: 

```cpp
void example_1(int i)
{
  switch (i)
  {
  case 1:
    DoSmth1();
    break;
  default: // <=
    DoSmth42();
    break;
  case 3:
    DoSmth3();
    break;
  }
}
```

Fixed code:

```cpp
void example_1(int i)
{
  switch (i)
  {
  case 1:
    DoSmth1();
    break;
  case 3:
    DoSmth3();
    break;
  default:
    DoSmth42();
    break;
  }
}
```

Example 2: 

```cpp
enum WEEK
{
  SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY
} weekDay;

void example_2()
{
  int isWorkday;

  switch (weekDay)
  {
  case MONDAY:
  case TUESDAY:
  case WEDNESDAY:
  case THURSDAY:
  case FRIDAY:
    isWorkday = 1;
    break;
  case SATURDAY:
  case SUNDAY:
    isWorkday = 0;
    break;
  default: // <=
    break;
}
```

Fixed code:

```cpp
enum WEEK
{
  SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY
} weekDay;

void example_2()
{
  int isWorkday;

  switch (weekDay)
  {
  case MONDAY:
  case TUESDAY:
  case WEDNESDAY:
  case THURSDAY:
  case FRIDAY:
    isWorkday = 1;
    break;
  case SATURDAY:
  case SUNDAY:
    isWorkday = 0;
    break;
  default:
    assert(false);
    break;
}
```