Coding guidelines: 5.1

From: Douglas Gregor (gregod_at_[hidden])
Date: 2001-07-07 11:12:32

5.1 states "Use a separate line for opening and closing braces". In "Code 
Complete", Steve McConnell considers the following three styles:

// 1
if (cond) {
  stmt1;
  stmt2;
}

// 2
if (cond)
{
  stmt1;
  stmt2; 
}

// 3
if (cond)
  {
  stmt1;
  stmt2; 
  }

5.1 suggests style #2, which is the only one of the three that McConnell says 
_not_ to use, because it violates his "Fundamental Theorem of Formatting." 
Essentially, the formatting doesn't fit the logic: without whitespace both 
above an below the entire code snippet, one can't tell that the block is part 
of the if statement. Code like this:

// A
foo = wibble + bar;
{
  stmt1;
  stmt2;
}

looks very similar to #2, but there is no relation between the block and the 
line before it. Throw in an identifier that looks like a statement (for_each, 
perhaps?) and it becomes more confusing. While I've not seen code like "A" 
often in C++ (it's more common in C when the programmer needs a temporary 
variable), it would be used more often when using the 
resource-acquisition-is-initialization methodology.

McConnell also cites a study that found no statistically significant 
difference between #1 and #3 regarding readability and understandability of 
code. Between these two it is a matter of personal preference, but I think 
that there is good reason not to accept the style proposed by 5.1.

I personally would opt for #1 because
        a) doesn't waste vertical space
        b) more common historically

        Doug