Function pointer without arguments types?

I was trying to declare a function pointer that points to any function that returns the same type. I omitted the arguments types in the pointer declaration to see what error will be generated. But the program was compiled successfully and executed without any issue.

Is this a correct declaration? Shouldn't we specify the arguments types?

#include <stdio.h>
#include <stdlib.h>

void add(int a, int b)
{
    printf("a + b = %d", a + b);
}

void (*pointer)() = &add;

int main()
{
    add(5, 5);
    return 0;
}

Output:

a + b = 10