**非法使用記憶體導致的錯誤 **

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
struct test{
	char *str;
	int a;
	int b;
	int c;
};
int main(){
	struct test obj;
	strcpy(obj.str, "mike");//報錯
	printf("str = %s\n", obj.str);
}

成員指標指向data區或者棧區

#include<stdio.h>
#include<string.h>
struct Student{
	int age;
	char *name;
	int score;
};
int main01(){
	struct Student s;
	s.age = 18;
	s.name = "mike";//指標變數儲存了字元常量的首地址 
	s.score = 59;
} 
 

**成員變數指向棧區空間 **

#include<stdio.h>
#include<string.h>
int main02(){
	struct Student s;
	s.age = 18;
	char buf[100];
	s.name = buf;
	strcpy(s.name, "mike");
	s.score = 59;
	//我們定義了一個字元型的陣列，將name指向的棧區的buf
} 

成員指標指向堆區空間

#include<stdio.h>
#include<string.h>
int main03(){
	struct Student s;
	s.age = 18;
	s.name = (char *)malloc(strlen("mike") + 1);
	strcpy(s.name, "mikejinagabcsb");
	s.score = 59;
	printf("%d, %s, %d\n", s.age, s.name, s.score);
	if(s.name != NULL)
	{
		free(s.name);
		s.name = NULL;
	}
}