storage class 2: Functions, The C Puzzle book

職業訓練
https://qiita.com/kaizen_nagoya/items/95368b63fa21d64271ec

Programmer, Day 6
https://qiita.com/kaizen_nagoya/items/632d8f191268e88eb86a

C Puzzle Bookの有り難み5つ、C言語規格及びCコンパイラの特性を認識, error(21), coding(28)
https://qiita.com/kaizen_nagoya/items/d89a48c1536a02ecdec9

The C Puzzle Book
https://efrei.poupa.net/Programmation%20en%20C/Cours/The_C_Puzzle_Book.pdf

defs.h "The C Puzzle Book"
https://qiita.com/kaizen_nagoya/items/6d284651ac1244963bd9

sc2.c

#define LOW 0
#define HIGH 5
#define CHANGE 2

int i=LOW;

void main(void)
{
        auto int i=HIGH;
        reset( i/2 ); PRINT1(d,i);
        reset( i=i/2 ); PRINT1(d,i);
        i = reset( i/2 ); PRINT1(d,i);

        workover(i); PRINT1(d,i);       // (Storage Classes 2.1)
}

int workover(int i)
{
        i = (i%i) * ((i+1)/(2*i) + 4);
        PRINT1(d,i);
        return(i);
}

int reset(int i)
{
        i = i<=CHANGE ? HIGH : LOW;
        return(i);
}

bash

$ gcc sc2a.c
sc2a.c: In function ‘main’:
sc2a.c:12:9: warning: implicit declaration of function ‘reset’ [-Wimplicit-function-declaration]
   12 |         reset( i/2 ); PRINT1(d,i);
      |         ^~~~~
sc2a.c:16:9: warning: implicit declaration of function ‘workover’ [-Wimplicit-function-declaration]
   16 |         workover(i); PRINT1(d,i);       // (Storage Classes 2.1)
      |         ^~~~~~~~
inst19@teachB:~$ ./a.out
i = 5
i = 2
i = 5
i = 0
i = 5