Pointers & Functions

Pointers and Functions Functions can take pointers: C equivalent to pass by ref #include <iostream> using namespace std; //C++ style void doubleVariable(int& x) { x = x * 2; } //C style void doubleVariableCStyle(int* x) { *x = (*x) * 2; } int main() { int num = 10; cout << num << endl; doubleVariable(num); cout << num << endl; doubleVariableCStyle(&num); cout << num <<#include <iostream> using namespace std; //C++ style void doubleVariable(int& x) { x = x * 2; } //C style void doubleVariableCStyle(int* x) { *x = (*x) * 2; int main() { int num = 10; cout << num << endl; doubleVariable(num); doubleVariableCStyle(&num); return 0; endl; return 0; }

Passing Pointers Pointers used like reference params: p1 p2 x 5 y 4

Passing Pointers Pointers used like reference params: temp p1 p2 x 5 y 4

Passing Pointers Pointers used like reference params: temp 5 p1 p2 x 5 y 4

Passing Pointers Pointers used like reference params: temp 5 p1 p2 x 4 y 4

Passing Pointers Pointers used like reference params: temp 5 p1 p2 x 4 y 5

Passing Pointers Pointers used like reference params: p1 p2 x 4 y 5

Passing Pointers Directly passing pointers p1 p2 x 5 pt1 0x004 pt2

Passing Pointers Directly passing pointers – addresses copied Can change x/y or p1/p2 Can't change pt1 / pt2 p1 0x004 p2 0x008 x 5 pt1 0x004 pt2 0x008 y 4

Passing Pointers Passing references to pointers p1 p2 x 5 pt1 0x004 y 4

Passing Pointers References to pointers temp References to pointers Can change the pointers themselves p1 p2 x 5 pt1 0x004 pt2 0x008 y 4

Passing Pointers References to pointers temp 0x004 References to pointers Can change the pointers themselves p1 p2 x 5 pt1 0x004 pt2 0x008 y 4

Passing Pointers References to pointers temp 0x004 References to pointers Can change the pointers themselves p1 p2 x 5 pt1 0x008 pt2 0x008 y 4

Passing Pointers References to pointers temp 0x004 References to pointers Can change the pointers themselves p1 p2 x 5 pt1 0x008 pt2 0x004 y 4

Passing Pointers References to pointers Can change the pointers themselves p1 p2 x 5 pt1 0x008 pt2 0x004 y 4

Return Pointers Can return a pointer from a function:

Returning Pointers Can return pointer – better not be to local variable

Returning Pointers Can return pointer – better not be to local variable x 10 pt

Returning Pointers Can return pointer – better not be to local variable x 10 pt 0x110 p 0x110

Returning Pointers Can return pointer – better not be to local variable p 0x110