下面的程序各自独立，请问执行下面的四个TestMemory 函数各有什么样的结果？①void GetMemory（char

下面的程序各自独立，请问执行下面的四个TestMemory 函数各有什么样的结果？

①void GetMemory(char * p)

{

p = (char * )malloc(100);

}

void TestMemory (void)

{

char *str = NULL;

GetMemory (str);

strcpy(str, "hello world");

prinff(str);

}

② char * GetMemory (void)

{

char p[ ] = "hello world";

return p;

}

void TestMemory (void)

{

char * str = NULL;

str = GetMemory();

printf(str);

}

③void GetMemory(char * * p, int num)

{

* p = (char * )malloc(num);

}

void TestMemory (void)

{

char * str = NULL;

GetMemory(&str, 100);

strcpy(str, "hello" );

printf(sir);

}

④void TestMemory (void)

{

char *str = (char * )malloe(100);

strepy (str, "hello" );

free (str );

if(str ! = NULL)

{

strepy(str, "world" );

printf(str);

}

}