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Why i cannot declare default arguments for member functions of a managed type or generic functions? C# 4.0 introduced Named and Optional Arguments; there is a similar thing for CLI?
I do not understand why is not possible to declare a method like this:
void Optional(int argument = 0);
And then when I call Optional(); the compiler does not translate this call into: Optional(0);.
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C does not support optional parameters.
First of all, to check if there is an argument, you should use the argc variable of the main(int argc, char** argv) , which indicates the length of your argv array.
The getopt() is one of the built-in C function that are used for taking the command line options. The syntax of this function is like below − getopt(int argc, char *const argv[], const char *optstring) The opstring is a list of characters. Each of them representing a single character option.
By Params Keyword: You can implement optional parameters by using the params keyword. It allows you to pass any variable number of parameters to a method. But you can use the params keyword for only one parameter and that parameter is the last parameter of the method.
It looks like the C++/CLI Compiler doesn't emit the correct IL directive for that. It doesn't emit the directive .param [1] = int32(0), which C# uses for recognizing default parameters. If you open the generated assembly in ILDasm, you'll see it.
A way that compiles would be to use the attributes Optional and DefaultParameterValue from the System::Runtime::InteropServices namespace, but C# doesn't use those for default parameters, so currently there's no easy way around creating an overload.
You can find the question asking about those Attributes here: https://stackoverflow.com/a/4974528/93652
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