In c# what does mean “< ? :”? [duplicate]

Answer 1

This is called a conditional operator, which is a type of ternary operator - as it takes 3 variables.
It is equivalent to

if(a < b)
{ 
   return c + " ";
}
else 
{
   return "text" + " ";
}

Answer 2

It is a ternary operator.

condition ? truePart : falsePart

It means if a is less then b then return c else return "text". Both values will have " " appended before returning...

Oh, but please don't use the variable names a, b and c in your own code :)

Answer 3

It is basically a short way of writing if else condition

if a is less then b
    then return c + " ";
otherwise 
    return "text" + " ";