Introduction to Pointers Lesson xx

1. Introduction to PointersLesson xx

2. Objectives • Memory setup • Pointer declaration • Address operator • Indirection • Printing addresses or pointers

3. Memory Setup 10 a (1ab) int a = 10; float x = 17.24; char c = ‘q’; 17.24 (2fe) x ‘q’ c (3cd)

4. Address 10 a (1ab) int a = 10; float x = 17.24; char c = ‘q’; 17.24 (2fe) x ‘q’ c (3cd) 5fb

5. Pointer Declaration 10 a (1ab) int a = 10; float x = 17.24; char c = ‘q’; int *ptr; 17.24 (2fe) x ‘q’ c (3cd) ptr

6. Address Operator & 10 a (1ab) int a = 10; float x = 17.24; char c = ‘q’; cout << a; cout << &a; 17.24 (2fe) x ‘q’ c (3cd)

7. Initializing a Pointer Variable 10 a (1ab) int a = 10; float x = 17.24; char c = ‘q’; int *ptr; ptr = &a; 17.24 (2fe) x ‘q’ c (3cd) 1ab ptr

8. Different Interpretation 10 a (1ab) int a = 10; float x = 17.24; char c = ‘q’; int *ptr; ptr = &a; 17.24 (2fe) x ‘q’ c (3cd) 1ab ptr

9. Redrawing a 1ab 10 (1ab) ptr int a = 10; float x = 17.24; char c = ‘q’; int *ptr; ptr = &a; 17.24 (2fe) x ‘q’ c (3cd)

10. Sample Pointer Program #include <iostream> using std::cout; using std::endl; int main() { int y, cc = 10; int* intptr; intptr = &cc;   y = *intptr; *intptr= 32;cout << y <<* intptr << intptr <<& intptr << endl;   return 0; }

11. Setting up Variables int y, cc = 10; int* intptr; intptr = &cc;   y = *intptr; *intptr= 32; cout << y <<* intptr << intptr <<& intptr << endl; y (1ab) 10 cc (4fe)

12. Setting up a Pointer int y, cc = 10; int* intptr; intptr = &cc;   y = *intptr; *intptr= 32;cout << y <<*intptr << ptr <<&intptr << endl; ; y (1ab) intptr 10 cc (4fe)

13. Initializing a Pointer int y, cc = 10; int* intptr; intptr = &cc;   y = *intptr; *intptr= 32; cout << y <<*intptr <<intptr <<&intptr << endl; y (1ab) 4fe intptr 10 cc (4fe)

14. Indirection on the Right int y, cc = 10; int* intptr; intptr = &cc; y = *intptr; *intptr= 32;cout << y <<* intptr << intptr <<& intptr << endl; 10 y (1ab) 4fe intptr 10 cc (4fe)

15. Indirection on the Left int y, cc = 10; int* intptr; intptr = &cc;y = *intptr; *intptr= 32;cout << y <<*intptr << intptr <<& intptr << endl; 10 y (1ab) 4fe intptr 32 cc (4fe)

16. Address of a Pointer Variable int y, cc = 10; int* intptr; intptr = &cc;  y = *intptr; cout << y <<*intptr <<intptr<<&intptr << endl; 10 y (1ab) 4fe intptr (55a) 32 cc (4fe)

17. Printing Pointers int y, cc = 10; int* intptr; intptr = &cc;  y = *intptr; cout << y <<*intptr <<intptr <<&intptr << endl; 10 y (1ab) 4fe intptr (55a) 32 cc (4fe) Output 10 32 4fe 55a

18. Summary • Memory setup • Pointer declaration • Address operator • Indirection • Printing addresses or pointers