CODEWITHSUNDEEP
c
user3125865
user3125865

Reputation: 31

How can I build a function that can receive 3 or 4 arguments ?

I know it's a basic question ,

How can I build\write a function that can receive 3 or 4 arguments ?

Or more general , How can i write a function that can receive unknown number of arguments ?

Thanks !

Upvotes: 1

Views: 139

Answers (3)

rullof
rullof

Reputation: 7434

To define a function with an unknown number of arguments the first one must be known. Then you have to include the stdarg.h library to access the arguments using it's functions: va_start, va_args, va_en and the type va_list.

In general the function is defined this way. Note that the first argument is not always of type int. It can be const char * for more controle on your arguments. for exemple in the printf() function.

type myFunction(int n, ...)
{
    int i;
    va_list args;
    va_start(args, n);
    for (i=0; i<n; i++){
    // your argument is va_arg(args, int);
    //... do something with your aruments
    }
    va_end(args);
    // return your value
}

check these resources for more about stdarg.h http://www.cplusplus.com/reference/cstdarg/ or http://en.wikipedia.org/wiki/Stdarg.h

Upvotes: 5

harper
harper

Reputation: 13690

You need a function with a variadic parameter list. Use ellipses to define it:

void foo(int first, ...)
{
}

Use var_args to parse the parameters. The first parameter is usually used to

  • address the other parameters
  • control how the other parameters shall be treated

Upvotes: 4

Julio
Julio

Reputation: 401

For the more general aspect, you can store the arguments in an array. And you can then pass a pointer of the array or the array itself to the actual function. This permits you to manipulate those arguments.

Upvotes: 0

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