[ACCEPTED]-What does typedef do in C++-typedef
This means that whenever you create a SetInt, you 3 are actually creating an object of set<int, less<int> >.
For 2 example, it makes the following two pieces 1 of code equivalent:
SetInt somevar;
and
set<int, less<int> > somevar;
From Wikipedia:
typedefis a keyword in the C and C++ programming 5 languages. It is used to give a data type 4 a new name. The intent is to make it easier 3 for programmers to comprehend source code.
In 2 this particular case, it makes SetInt a type name, so 1 that you can declare a variable as:
SetInt myInts;
You can just use SetInt after the typedef as if you are 1 using set<int, less<int>>. Of course, typedef is scope aware.
It makes an alias to the type called SetInt, which 3 is equivalent to set<int, less<int> >.
About your question about 2 less, that refers to std::less, the comparer that 1 set will use to sort your objects.
A typedef in C/C++ is used to give a certain 10 data type another name for you to use.
In 9 your code snippet, set<int, less<int> > is the data type you 8 want to give another name (an alias if you 7 wish) to and that name is SetInt
The main purpose 6 of using a typedef is to simplify the comprehension 5 of the code from a programmer's perspective. Instead 4 of always having to use a complicated and 3 long datatype (in your case I assume it 2 is a template object), you can choose a 1 rather simple name instead.
The code means that you give an alias or 4 name (SetInt) to the
set<int, less<int>>
object...i.e. instead 3 of always calling the object as
set<int, less<int>>
you can 2 just give SetInt as the name and call the 1 object.... just like
int i;
eg:
SetInt setinteger;
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