A summary of the introduction of pointers as parameters in functions

A. form void Func (char* ptr).

Note that this is a copy of the pointer, which is essentially the way to pass the value. Create a new pointer variable inside the function, and then assign the value that PTR points to the local pointer variable. Any modification to the local variable's address does not affect PTR.

1 intNewint=1;2 3 voidChangeloc (int*ptr)4 {5ptr=&Newint;6 }7 8 intMain ()9 {Ten intnum=2; One int* ptr=&num; Acout<<ptr<<Endl; - Changeloc (PTR); -cout<<ptr<<Endl; the } -  - /* - Results: + 2 - 2 + */

Two. If you want the view to modify the address of an incoming parameter in a local variable, you can use a pointer reference or pointer to a pointer method.

Source: http://www.cnblogs.com/li-peng/

Using pointers to pointers

Show pointers as arguments using pointers

void func (int **p) {    *p = &m_value;    You can also allocate memory according to your needs    *p = new int;    **p = 5;} int main (int argc, char *argv[]) {    int n = 2;    int *PN = &n;    cout << *pn << Endl;    Func (&PN);    cout << *PN <<endl;    return 0;}

Let's take a look at the func (int **p) method

• P: Is a pointer pointer, where we do not modify it, otherwise we will lose the pointer to the address of the pointer
• *p: Is the pointer that is pointed to, is an address. If we modify it, the content of the pointer being directed is modified. In other words, we are modifying the *PN pointer in the main () method
• **p: Two times the dereference is the *pn of the main () method

Reference to Pointers

Look again at the reference code of the pointer

int m_value = 1;void func (int *&p) {    p = &m_value;    You can also allocate memory    p = new int according to your needs;    *p = 5;} int main (int argc, char *argv[]) {    int n = 2;    int *PN = &n;    cout << *pn << Endl;    Func (PN);    cout << *PN <<endl;    return 0;}

Take a look at the func (int *&p) method

• P: is a reference to a pointer, the *PN in the main () method
• *p: Is the content of the PN point in the main () method.

Three. Effective C + +: Terms of---never return a reference to a local object, and do not return a reference to a pointer inside a function that is initialized with new

1 Char* out()2 {3 /*wrong*/4 5 /*Version16 char* array=new char[10];7 cin>>array;8 return array;9 */Ten  One /*Version2 A string k= "Hello,world"; - return k; - */ the  -}

A summary of the introduction of pointers as parameters in functions