Update: Since ES6, you can simply use the spread syntax when calling the function: func(…arr); Since ES6 also if you expect to treat your arguments as an array, you can also use the spread syntax in the parameter list, for example: function func(…args) { args.forEach(arg => console.log(arg)) } const values = [‘a’, ‘b’, ‘c’] func(…values) … Read more
Yes, a T… is only a syntactic sugar for a T[]. JLS 8.4.1 Format parameters The last formal parameter in a list is special; it may be a variable arity parameter, indicated by an elipsis following the type. If the last formal parameter is a variable arity parameter of type T, it is considered to … Read more
Varargs are useful for any method that needs to deal with an indeterminate number of objects. One good example is String.format. The format string can accept any number of parameters, so you need a mechanism to pass in any number of objects. String.format(“This is an integer: %d”, myInt); String.format(“This is an integer: %d and a … Read more
To pass the ellipses on, you initialize a va_list as usual and simply pass it to your second function. You don’t use va_arg(). Specifically; void format_string(char *fmt,va_list argptr, char *formatted_string); void debug_print(int dbg_lvl, char *fmt, …) { char formatted_string[MAX_FMT_SIZE]; va_list argptr; va_start(argptr,fmt); format_string(fmt, argptr, formatted_string); va_end(argptr); fprintf(stdout, “%s”,formatted_string); }
It means that zero or more String objects (or a single array of them) may be passed as the argument(s) for that method. See the “Arbitrary Number of Arguments” section here: http://java.sun.com/docs/books/tutorial/java/javaOO/arguments.html#varargs In your example, you could call it as any of the following: myMethod(); // Likely useless, but possible myMethod(“one”, “two”, “three”); myMethod(“solo”); myMethod(new … Read more
There’s no such thing as a List<int> in Java – generics don’t support primitives. Autoboxing only happens for a single element, not for arrays of primitives. As for how to correct it – there are various libraries with oodles of methods for doing things like this. There’s no way round this, and I don’t think … Read more
In C++11 you have two new options, as the Variadic arguments reference page in the Alternatives section states: Variadic templates can also be used to create functions that take variable number of arguments. They are often the better choice because they do not impose restrictions on the types of the arguments, do not perform integral … Read more
The *args and **kwargs is a common idiom to allow arbitrary number of arguments to functions as described in the section more on defining functions in the Python documentation. The *args will give you all function parameters as a tuple: def foo(*args): for a in args: print(a) foo(1) # 1 foo(1,2,3) # 1 # 2 … Read more