variadic-functions

In Swift, how do you convert an Array to a Tuple? The issue came up because I am trying to call a function that takes a variable number of arguments inside a function that takes a variable number of arguments. // Function 1 func sumOf(numbers: Int...) -> Int { var sum = 0 for number in numbers { sum += number } return sum } // Example Usage sumOf(2, 5, 1) // Function 2 func averageOf(numbers: Int...) -> Int { return sumOf(numbers) / numbers.count } This averageOf implementation seemed reasonable to me, but it does not compile. It gives the following error when you try to call sumOf(numbers) :

is it possible to create a function in java that supports any number of parameters and then to be able to iterate through each of the parameter provided to the function ? thanks kfir Java has had varargs since Java 1.5 (released September 2004). A simple example looks like this... public void func(String ... strings) { for (String s : strings) System.out.println(s); } Note that if you wanted to require that some minimal number of arguments has to be passed to a function, while still allowing for variable arguments, you should do something like this. For example, if you had a function that

I have a variadic function which takes a float parameter. Why doesn't it work? va_arg(arg, float) dasblinkenlight Parameters of functions that correspond to ... are promoted before passing to your variadic function. char and short are promoted to int , float is promoted to double , etc. 6.5.2.2.7 The ellipsis notation in a function prototype declarator causes argument type conversion to stop after the last declared parameter. The default argument promotions are performed on trailing arguments. The reason for this is that early versions of C did not have function prototypes; parameter types

I'm writing a promotion template alias similar to boost::promote but for C++11. The purpose of this is to avoid warnings when retrieving arguments from varidic functions. e.g. template <typename T> std::vector<T> MakeArgVectorV(int aArgCount, va_list aArgList) { std::vector<T> args; while (aArgCount > 0) { args.push_back(static_cast<T>(va_arg(aArgList, Promote<T>))); --aArgCount; } return args; } The Promote template alias promotes the type following the default argument promotion for variadic arguments: 1) An integer that's smaller than an int is promoted to int 2) A float is promoted to

I need to create in an iOS application a fake va_list to pass to a NSString initWithFormat:arguments: function, this is my code: NSArray *fixedArguments = [[NSArray alloc] initWithArray:arguments]; NSRange range = NSMakeRange(0, [fixedArguments count]); va_list fakeArgList = (va_list)malloc(sizeof(NSString *) * [fixedArguments count]); __unsafe_unretained id *ptr = (__unsafe_unretained id *)fakeArgList; [fixedArguments getObjects:ptr range:range]; content = [[NSString alloc] initWithFormat:outputFormat arguments:(va_list)fakeArgList]; free(fakeArgList); The compiler complains with this message

How to count the no of arguments passed to the function in following program: #include<stdio.h> #include<stdarg.h> void varfun(int i, ...); int main(){ varfun(1, 2, 3, 4, 5, 6); return 0; } void varfun(int n_args, ...){ va_list ap; int i, t; va_start(ap, n_args); for(i=0;t = va_arg(ap, int);i++){ printf("%d", t); } va_end(ap); } This program's output over my gcc compiler under ubuntu 10.04: 234561345138032514932134513792 so how to find how many no. of arguments actually passed to the function? You can't. You have to manage for the caller to indicate the number of arguments somehow. You can:

This question already has an answer here: Forward an invocation of a variadic function in C 10 answers I have approximately 30 variadic functions. Each one accepts a path as the final argument, e.g.: bool do_foo(struct *f, int q, const char *fmt, ...) In each function, I have to check that the expanded format is less then or equal to a certain size. So, I find myself copy / pasting the same chunk of code to check for how many characters vsnprintf() didn't print, set errno accordingly and bail out of the write. What I would like to do is write a function to do this, which would return a

I am confused about the spread syntax and rest parameter in ES2015. Can anybody explain the difference between them with proper examples? TbWill4321 When using spread, you are expanding a single variable into more: var abc = ['a', 'b', 'c']; var def = ['d', 'e', 'f']; var alpha = [ ...abc, ...def ]; console.log(alpha)// alpha == ['a', 'b', 'c', 'd', 'e', 'f']; When using rest arguments, you are collapsing all remaining arguments of a function into one array: function sum( first, ...others ) { for ( var i = 0; i < others.length; i++ ) first += others[i]; return first; } console.log(sum(1,2,3,4)