###### tags: `learning` `zxm`

zxm QQ THX
===
# -Wall -Wmaybe-uninitialized

# 0

int main(void){
     int *a;
     *a = 11;
 
     printf("%p\n", a);
     printf("%p\n", &a);
     printf("%d\n", *a); // 11
     
     a = malloc(sizeof(int));
  
     printf("%p\n", a);
     printf("%p\n", &a);
     printf("%d\n", *a); // sometimes 0 sometimes 1
}

運氣好可以跑 但是是犯戒的
# 1

int main(void){
     int *a;
     *a = 11;
 
     printf("%p\n", a);
     printf("%p\n", &a);
     printf("%d\n", *a);
     
     a = malloc(sizeof(int));
  
     printf("%p\n", a);
     printf("%p\n", &a);
     printf("%d\n", *a); 
 
     int *b;
     printf("%p\n", b); // Segmentation fault (core dumped)

}

Segmentation fault (core dumped)

# 2

int main(void){
    int *newh;
    printf("%p\n", newh);

(nil)

# 3

int main(void){
    int *newh;
    *newh = 10;
    printf("%p\n", newh);

Segmentation fault (core dumped)