Different meanings of omitting parameters in function declarations of C and C + +

Have always thought that C + + is shaped like

int func ();

Such a function declares its meaning as a function of a parameter void (without arguments). Today, however, when I look at C + +, I suddenly see this sentence:

For functions with empty parameter tables, C and C + + differ greatly. In the C language, declare int  func2 (); "A function that can take any number of arbitrary arguments (arbitrary numbers, any type)." This interferes with type checking. In the C+ + language, it means "functions without parameters".

The teacher did not say, the school textbooks did not mention, with curiosity, I deliberately tried

TEST.c

1#include <stdio.h>2 3 voidFun ();4 intMain ()5 {6Fun1,1);7 8     return 0;9 }Ten  One voidFunintAintb) A { -printf"%d\n", A +b); -}

-wall test.c-o test$./test
  2

$ mv test.c test.cpp$ G+ +-wall test.cpp-o testtest.cpp: in function 'int  main () ': test.cpp: 6:Error: Too many arguments to function ' void fun  '  (11 );   ^test.cpp:3:6void fun ();       ^~~

It also explains why the main function is written like this.

int Main (void)

Different meanings of omitting parameters in function declarations of C and C + +