C错误：在'...'标记之前预期';'，'，'或'）'

Question

I have a problem. The concept of Object Oriented Programming in C got homework. I need to use variadic functions. But I get a mistake. I'd appreciate it if you could help me. I'm new to encoding.

RastgeleKarakter.h :

#ifndef RASTGELEKARAKTER_H
#define RASTGELEKARAKTER_H
struct RASTGELEKARAKTER{
// code
};

RastgeleKarakter SKarakterOlustur(int...); // prototype
void Print(const RastgeleKarakter);
#endif

RastgeleKarakter.c :

#include "RastgeleKarakter.h"
#include "stdarg.h
RastgeleKarakter SKarakterOlustur(int... characters){
//code
}

Error :

 make
gcc -I ./include/ -o ./lib/test.o -c ./src/Test.c
In file included from ./src/Test.c:3:0:
./include/RastgeleKarakter.h:17:38: error: expected ';', ',' or ')' before '...' token
RastgeleKarakter SKarakterOlustur(int...);

I don't know how many parameters there are. I want to solve this with the variable function.

Answer 1

Variadic arguments in C are untyped and unnamed. The correct prototype for a variadic function is:

returnType functionName(type1 ordinaryArg1, type2 ordinaryArg2, ...)

You need at least one ordinary arguments before the ... . You can only access the variadic arguments through the functions from stdarg.h .

Answer 2

The parameter list should not have a type nor a name

RastgeleKarakter SKarakterOlustur(int count, ...)

{
  va_list args;
  va_start(args, count);
  int i = va_arg(args, int);
}

Use the macros defined in stdarg.h header file to access the parameter list. further reading

If by your original deceleration, you meant that all members of the parameter list are integers, and since you will be supplying the count anyway, consider changing it to int count, int * list

Answer 3

The error says that the compiler expects one of the following before the ellipsis: -semicolon -comma -closing parentheses

So, the prototype is not declared correctly. The declaration needs at least one named variable and the last parameter must be the ellipsis.

For example, if you intend to pass integers to the method, the declaration could be as follows:

int  sum (int count, ...);