[C언어 #44] 메모리 할당 해제 (malloc / free) - 구조체 (struct) 적용

c언어 메모리 할당 해제 (malloc / free) - 구조체 (struct)에 적용

 

 

구조체를 활용하는 기존 방식

ex. struct 'vehicle'

/* Passing structures using pointers */
#include <stdio.h>
 
// Structure vehicle
struct vehicle { int x, y; };
 
// type definition structure 'vehicle'
typedef struct vehicle vehicle;
 
// drive vehicle
struct vehicle drive(struct vehicle t, int dx, int dy) {
    t.x = t.x + dx;
    t.y = t.y + dy;
    return t;
}
 
int main() {
    struct vehicle truck = { 11, 27 };
    printf("truck - x: %d, y: %d\n", truck.x, truck.y);
 
    // Drive and print result
    truck = drive(truck, 17, 23);
    printf("truck - x: %d, y: %d\n", truck.x, truck.y);
}

 

 

메모리 할당을 활용하여 구조체 초기화 후 좌표 이동

/* Struct malloc */
#include <stdio.h>
#include <stdlib.h>
 
// Structure 'vehicle'
struct vehicle { int x, y; };
 
// typedef struct 'vehicle'
typedef struct vehicle vehicle;
 
// Allocate structure
vehicle *truck(int x0, int y0) {
    vehicle *t = malloc(sizeof(struct vehicle));
    t->x = x0;
    t->y = y0;
    return t;
}
 
// Drive truck
void drive(struct vehicle *t, int dx, int dy) {
    t->x = t->x + dx;
    t->y = t->y + dy;
}
 
int main() {
    vehicle truckData = { 11, 27 };
    vehicle *truck = &truckData;
    printf("truck - x: %d, y: %d\n", truck->x, truck->y);
    
    drive(truck, 17, 23);
    printf("truck - x: %d, y: %d\n", truck->x, truck->y);
}