Передача структуры в функцию, используя указатель

#include <stdio.h>
 
struct person
{
    int age;
    char name[20];
};
 
 
void change_struct_andriy(struct person *p_andriy);
 
structure_and_pointers(void)    // MAIN function in file <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
{
   
        struct person andriy;
        struct person *p_andriy = &andriy;
                p_andriy->age=22;
        strcpy(p_andriy->name, "Andriy");
        printf("Before change: Name: %s, age: %d", p_andriy->name, p_andriy->age);
        change_struct_andriy(p_andriy);
                printf("After change: Name: %s, age: %d", p_andriy->name, p_andriy->age);
}
 
 
void change_struct_andriy(struct person *p_andriy)
{
 
   // do something with p_andriy ...
}

void change_struct_andriy(struct person *p_andriy);

#include <stdio.h>
 
void pointers_on_functions(void);
 
static void my_sum_p(float a_f, float b_f, float *sum_f);
static void my_sub_p(float a_f, float b_f, float *sub_f);
static void my_mul_p(float a_f, float b_f, float *mul_f);
static void my_div_p(float a_f, float b_f, float *div_f);
 
void structure_and_pointers(void);                    // Main function in structure_and_pointers file
static void change_element_of_structure(void);        // Change elements structure Top
static void measure_size_structures(void);            // Measure size Top and struct_variable
static void create_object_structure(void);
static void create_local_structure(void);
static void fill_strunc_using_pointer(struct person *igor);
static void print_student_void(void *qwerty);
static void print_srt(const char *c_str);
void change_struct_andriy(struct person *p_andriy);

#include <stdio.h>
#include "structure.h"
 
static struct Data
{
        int x;
        int y;
} Point;                                       // Create new tipe data Point from Data
 
static struct Data Top;             // Create new tipe data Top from Data
 
// Typedef - create new type Data
// It method better than previous
typedef struct
{
    int q;
    int w;
} struct_variable;
 
// one structure inside another structure
/*
 create strucrure a and b which havs structure struct_variable
*/
typedef struct
{
    struct_variable a;
    struct_variable b;
    int j;
} coordinates;                          // Create object coordinates structure
 
struct person
{
    int age;
    char name[20];
};
 
struct team
{
    char name[20];
    int age;
};
 
//void change_struct_andriy(struct person *p_andriy);
 
structure_and_pointers()    // MAIN function in file <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
{
    change_element_of_structure();      // Change elements global structure Top in function
    measure_size_structures();          // Measure size Top and struct_variable
    create_object_structure();          // Create local object
    create_local_structure();                       // Same like previous
 
    // Structure and pointer on it ------------------------------------------------
    struct person boris;                                        // Create boris object from person
    struct person *p_boris=&boris;                          // Create pointer on boris object
    p_boris->age=99;                                                        // Write int
    strcpy(p_boris->name, "Boris");                         // Write string
    printf("Name: %s, age BORIS: %d\r\n",p_boris->name ,p_boris->age);
    // ----------------------------------------------------------------------------
 
        // create local strutc and transfet adress it in function  -------------------
    struct person igor;                                                 // Create new object igor from struct person
    strcpy(igor.name, "Igor");
    igor.age=34;
    printf("Before function. NAME: %s, AGE: %d\r\n", igor.name, igor.age);
    fill_strunc_using_pointer(&igor);            //transfet adress it in function
    printf("After function. NAME: %s, AGE: %d\r\n", igor.name, igor.age);
    // ----------------------------------------------------------------------------
 
    //
        struct person andriy;
        struct person *p_andriy = &andriy;
    p_andriy->age=22;
        strcpy(p_andriy->name, "Andriy");
        printf("Before change: Name: %s, age: %d\r\n", p_andriy->name, p_andriy->age);
        change_struct_andriy(p_andriy);
    printf("After change: Name: %s, age: %d\r\n", p_andriy->name, p_andriy->age);
 
 
 
 
 
//----------------------------------------------------------------------------------
    // Create local anonime structure, create qwerty object
    // and transmit pointer on object on function print_student_void.
    struct                          // Create anonime local structure
    {
      char name[60];
      unsigned char a;
      unsigned char b;
    } qwerty;
    // Fill elements of structure
    strcpy(qwerty.name, "test");
    qwerty.a=20;
    qwerty.b=30;
    print_student_void((void*)&qwerty);                                 // Transmit pointer structure in function
 
    // Create pointer on function     (not good method)
    // unsigned int *print_str_addr;                                                                    // Create pointer for function
    // print_str_addr = (unsigned int*)print_srt;                                       // Create pointer on function print_srt
    // printf ("addres function: 0x%08X \n\r", print_str_addr);         // Print address
    // printf ("addres function: 0x%08X \n\r", (unsigned int*)print_srt);           // same
    // // usint address of function
    // void (*print_str_new)(const char *c_str);
    // print_str_new = (void*)print_str_addr;
    // print_str_new("HELLO\r\n");                                                                      // Using pointer on function
 
    void (*print_str_new)(const char *c_str);         // Create pointer on some function
    print_str_new=&print_srt;                         // or without & (print_str_new=print_srt)
    print_str_new("HELLO");                           // transmit data in function
}
 
 
 
 
 
void pointers_on_functions(void)
{
  printf("functions_and_pointers\r\n");
  /*
  Create arrey pointers on several functions
  */
  void (*arith_operations[4])(float, float, float*) = {my_sum_p, my_sub_p, my_mul_p, my_div_p};
  float a=3. ,b=5, res=.0;
  for(unsigned char i=0; i<4; i++)
  {
    arith_operations[i] (a, b, &res);
    printf("Valye operation %hd is %f\n", i, res);
  }
}
 
 
static void my_sum_p(float a_f, float b_f, float *sum_f)
{
  *sum_f = a_f+b_f;
}
 
static void my_sub_p(float a_f, float b_f, float *sub_f)
{
  *sub_f = a_f-b_f;
}
 
static void my_mul_p(float a_f, float b_f, float *mul_f)
{
  *mul_f = a_f*b_f;
}
 
static void my_div_p(float a_f, float b_f, float *div_f)
{
  *div_f = a_f/b_f;
}
 
void change_element_of_structure(void)
{
  // Write data in elements STRUCTURE Top
  Top.x=88;
  Top.y=99;
  printf("Data from Top.x: %d\r\n", Top.x);
  printf("Data from Top.y: %d\r\n", Top.y);
}
 
void measure_size_structures(void)
{
  printf("Memory size struct_variable: %d\r\n", sizeof(struct_variable));
  printf("Memory size coordinates: %d\r\n", sizeof(coordinates));
}
 
/*
Create local object "kate", it object are local in it function.
*/
void create_object_structure(void)
{
 
  struct person kate = {31, "Kate"};            // Create object "kate" from structure "pointer" and writing data
  printf("Kate AGE: %d  Kate NAME: %s\r\n", kate.age, kate.name);
}
 
/*
Create local object oleg in function from struct "team"
It structure work only in this function
*/
void create_local_structure(void)
{
    static struct team oleg;                        // Create local objet oleg
    strcpy(oleg.name, "Oleg Demkiv");
    oleg.age=28;
 
    printf("Name worker: %s \r\n", oleg.name);
    printf("Age: %d\r\n", oleg.age);
}
 
/*
Function gets pointer on new structure igor
In function, for change element object structure igor we use ->
becouse we work with pointers in elements of structure.
*/
fill_strunc_using_pointer(struct person *igor)
{
    strcpy (igor->name, "lubomyr");
    igor->age;
    printf("In function. NAME: %s, AGE: %d\r\n", igor->name, igor->age);
}
 
// What different between it function and fill_strunc_using_pointer(struct person *igor)????
void print_student_void(void *qwerty)
{
    typedef struct
    {
        char name[60];
        unsigned char a;
        unsigned char b;
    } stdn;
 
    printf("%s, %d, %d \n\r", ((stdn*)qwerty)->name, ((stdn*)qwerty)->a, ((stdn*)qwerty)->b );
}
 
void print_srt(const char *c_str)
{
    printf("%s \n\r", c_str);
}
 
 
void change_struct_andriy(struct person *p_andriy)
{
    p_andriy->age=33;
    strcpy(p_andriy->name, "ANDRIY");
}