Trying c in Project form

#include <stdio.h>

#include "_ref.h"

static int sub()

{

staticintb = 0;

for (inti = 0; i < 5; i++)

{

b++;

}

returnb;

}

extern float sub1() // empty body float type return returns random space by default;

{

}

/*

remember to assign value to variable declaration;

static, extern does not work for direct referencing like "#include "_ref.c"", but works for "#include "_ref.h"" by running gcc cstringtest.c _ref.h _ref.c

*/

int main() // int return value is not mandatory to be specified, non-void by default int a=sub() returns 1;

{

inta = sub(); // sub() returns 5 when 1st called;

printf("a:%d\n", a);

intaa = sub(); // call sub() once again, the static value is accumulated to 10;

printf("aa:%d\n", aa);

floata1 = sub1();

printf("a1:%f\n", a1);

doublea2;

printf("a2:%f\n", a2);

inta3;

printf("a3:%d\n", a3);

floata4;

printf("a4:%f\n", a4);

{

constinta1 = 0;

// extern int ab; // extern is used to ref global variables defined in other files; like public to open public visit; if b does not exist, linker will throw error;

printf("a1:%d\n", a1);

printf("ab:%d\n", ab); // ab is static in header file, it is 0 here; static is used to hide from other files by being in header;

printf("ac:%d\n", ac); // ac does not need extern;

externint ad; // extern to use ad declared in _ref.c; or else ad is not declared in _ref.h;

ad = 58;

printf("ad:%d\n", ad);

}

p();

}

#ifndef REF_H

#define REF_H

int p(void);

static int ab;

int ac;

#endif

3. _ref.c