Details of level 2 pointers in C Language

Details of level 2 pointers in C Language
Use the C language pointer as the function return value:

The C language allows the function to return a pointer (Address). We call such a function a pointer function.

After the function is executed, all local data defined in the function is destroyed.

# Include

# Include

Char * strlong (char * d, char * e ){

If (strlen (d)> strlen (e )){

Return d;

} Else {

Return e;

}

}

Int main (){

Char * a = "taoshihan ";

Char * B = "taoaaaaaaa ";

Char * c;

C = strlong (a, B );

Printf ("c = % s", c );

Return 0;

}

Second-level pointer of C language (pointer to pointer ):

A pointer can point to a common type of data, such as int, double, and char. It can also point to a pointer type of data, such as int *, double *, and char.

If a pointer points to another pointer, we call it a second-level pointer or a pointer to the pointer.

# Include

Int main (){

Int e = 100;

Int * B = & e;

Int ** c = & B;

Printf ("% d, % d, % d \ n", e, * B, ** c );

Printf ("& e = % # x, B = % # x, & B = % # x, c = % # x \ n", & e, B, & B, c );

Return 0;

}

& E = 0xbfe7c530, B = 0xbfe7c530, & B = 0xbfe7c534, c = 0xbfe7c534

The address of e is 0xbfe7c530, B is the pointer address is 0xbfe7c530, and B points to e.

The address of the B pointer variable itself is 0xbfe7c534, and the address of the c pointer is 0xbfe7c534.