Functions with Default Arguments in C++ and C

[ankitdixit]

Hello Everyone, I want to know head to head comparison between the use of functions with default arguments in C++ and C. I am confused which is better work for function with default arguments. Can anyone know about it? As my knowledge C doesn’t. If such a function is called by passing argument(s) then those argument(s) are used by the function. Can anyone suggest me proper comparison?

[2kaud]

In C++, arguments from the right to to left can be provided with default values to be used by the function if the caller doesn't provide a specified parameter. These are most often used for arguments where there is typically a 'most used' value (default) with a specific argument only needing to be passed when this default is not appropriate. Working from the right, arguments can have a default specified until an argument isn't specified with a default. Then all the remaining arguments to the left can't have a default specified value. All arguments are used by the function in the same way - whether the value is the default value or the passed value.

A simple example:

void testfun(const std::string& str, char delim = '\n')
{...}

...

testfun("abcde");         // Uses '\n' as delim
testfun("zxcvb", ',');    // Uses , as delim

[wolle]

Can anyone suggest me proper comparison?

There is no need to resort to C to find guidance about C++ usage. C++ is a language in its own right with its own guidelines. See for example,

F.51: Where there is a choice, prefer default arguments over overloading
C.140: Do not provide different default arguments for a virtual function and an overrider

in the C++ Core Guidelines.

https://github.com/isocpp/CppCoreGui...eGuidelines.md

[ankitdixit]

Thanks to solving my problem, Now I am clear it to while C++ allows using a function with default arguments, C doesn’t. If such a function is called by passing argument(s) then those argument(s) are used by the function.

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