error: too many arguments to function add_two_numbers

[AmanDo T]

Trying to learn C and doing my practice on the Code::Blocks 10.05. I get this error trying to compile the following simple code given in the book I am using.

#include <stdio.h>

int main()
{
int var1, var2;
int add_two_numbers ();

var1 = 1;
var2 = 53;

add_two_numbers (var1, var2);
add_two_numbers (1, 2);

exit(0);
}
add_two_numbers (int a, int b) /* Add a and b */
{
int c;

c = a + b;
printf ("%d\n", c);
}

Any advise as what am I doing wrong?

[kamellion]

Exit does not exist in sdtio.h, you will need to include "#include <stdlib.h>"

add_two_numbers does not return int
void add_two_numbers(...)

move your prototype out of the main (also your prototype needs to know what variable types to expect)


I am quite rusty, but maybe this will help.
Take a systematic approach, first compile with calls to 'add_two_numbers'
commented out, if that works then uncomment one call and re-compile. Repeat this process until your program is successful.

Regards

#include <stdio.h>
#include <stdlib.h>
 
void add_two_numbers(int,int);
 
int main()
{
   int var1, var2;
   var1 = 1;
   var2 = 53;
   //add_two_numbers (var1, var2);
   //add_two_numbers (1, 2);
   exit(0);
};
 
void add_two_numbers (int a, int b) /* Add a and b */
{
   int c;
   c = a + b;
   printf ("%d\n", c);
};
 

[johny10151981]

kamellion already answered everything

The problem you have made is
you have declare your function like this

int add_two_numbers ();
 

but you have defined your function like this

int add_two_numbers (int, int)
{
...
}
 

and your compiler made that error cause it remember the declaration without variable

[Banfa]

You are compiling your C code using a C++ compiler. I can tell this because int add_two_numbers(); has different meanings in C and C++ and the error you are getting "too many arguments to function" is produced as a result of that difference in meaning.

Remember in C++ that you have to provide a complete function prototype before you call that function, however in C you don't although it is best practice. It is this requirement difference that has lead to the different meanings.

So the 2 means are (differences highlighted in bold)

C: A function exists called add_two_numbers that returns an int; I am not telling you anything about what parameters it takes.

C++: A function exists called add_two_numbers that returns an int; it takes no parameters.

In C++ the equivalent of int add_two_numbers(void);

In C when it sees the call add_two_numbers (1, 2); it compiles fine because the compiler, correctly, compiles the 2 parameters since it has no information about what parameters the function accepts and it doesn't need that information to compile the function call.

For the same code in C++ the compiler has been informed that the function takes 0 parameters so it produces an error since you have tried to pass 2 parameters into it.


If you are undertaking a course or project in C and writing C code it is generally a mistake to compile using a C++ compiler.