Question

I have a class which has a group of integers, say

foo()
{
  int a;
  int b;
  int c;
  int d;
  ....
  string s;
}

Now the question is for the best readbility, the init() function for foo(), should it look like

void init()
{
  a=b=c=d=1; //for some reason they are init to 1;
  s = "abc";
}

or

void init()
{
  a=1;
  b=1;
  c=1;
  d=1;
  s = "abc";
}

?

The reason for a string in class is a hint of other groups of same types might present and of course, the class might grow as requirement changes

EDIT: before this question goes too far, the intention of this question was simple:
In Effective C++ item 12 (prefer initialization to assignment in constructors), Scott uses chain assignment instead of a=c; b=c; I am sure he knows when to use what, but I also remembered the books I read also recommended to use int a; int b; which in similar case of assignments. In my program I have a similar situation of a group of related individual build-in types needs to be initialized and I have found by making a chain assignment does makes it easier to read especially if the class have many other different types instance variables. It seems to contradict with books I read and my memory, hence the question.

Answer 1

My personal preference is a=b=c=d for the following reasons:

1. It is concise, saves lines
2. It conveys the concept that (a/b/c/d) are initialized to the same thing, that they are related

However, caveat:

1. Don’t do that if a/b/c/d are not related (and just happens to be initialized to 1). You’ll reduce the readability of your code. Example:

   a=c=1; // Foo-function related

   b=d=1; // Bar-function related

2. Chaining assignments like this reduces the flexibility for you in the future to assign different initial values to the variables — because then you’ll have to break them up again.

Nevertheless, my personal recommendation is to chain assignments on variables that are related on concept/usage. In actual practice, the need to change an assignment usually doesn’t come up often so caveat #2 should not typically pose a problem.

Edit: My recommendation may go against published guidelines. See the comments.