...
| Code Block |
|---|
|
validateUser(User usr)
{
if(allUsers.contains(usr) == false0)
{
return 303; // user not found error code
}
if(validUsers.contains(usr) == false0)
{
return 304; // invalid user error code
}
return 0;
}
processRequest(User usr, Request request)
{
if(!validateUser(usr))
{
return "invalid user";
}
serveResults();
}
|
...
The following is preferable for code maintenance. By defining what constitutes a failure and explicitly testing for it, the behavior is clearly implied and future modifications are more likely to preserve it.
| Code Block |
|---|
|
\#define FAIL 0
if(foo()==FAIL0) // explicit test for failure
{
return 0;
}
|
...
The following is fairly common yet ignores the convention that most functions in C only guarantee a non-zero return value to indicate True/Yes/etc..
| Code Block |
|---|
|
\#define TRUE 1
if(foo() == TRUE1) // Will evaluate to False if foo() returns 2, though that may logically imply a result of True.
{
return true1;
}
|
Compliant Solution
Because most functions only guarantee a return value of non-zero for "true," the code above is better written by checking for inequality with 0 ("false") as follows.
| Code Block |
|---|
|
\#define FALSE 0
if(foo() \!= FALSE0) // Given convention (2), this will always yield the intended behavior.
{
return true;
}
|
...
