[C언어 #45] 메모리 할당 (malloc) - 구조체 (struct) 초기화

c언어 메모리 할당시 구조체 초기화 방법

 

 

메모리 할당 (malloc) 활용한 구조체

/* 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);
}

 

 

방법 1.

vehicle *truck(int x0, int y0) {
    vehicle *t = malloc(sizeof(struct vehicle));
    t->x = x0;
    t->y = y0;
    return t;
}

 

 

방법 2.

vehicle *truck(int x0, int y0) {
    vehicle *t = malloc(sizeof(struct vehicle));
    *t = (vehicle) { x0, y0 };    
    return t;
}

 

 

방법 3.

vehicle *truck(int x0, int y0) {
    vehicle *t = malloc(sizeof(struct vehicle));
    *t = (vehicle) { .x = x0, .y = y0 };
    return t;
}