Lecture Notes on Pointers

Introduction

• Purpose of discussing pointers
• Importance of pointers in C++

What are Pointers?

• Pointers are variables that store memory addresses.
• A pointer is a variable that holds the address of another variable.

Understanding Basic Pointer

• For example, in int num = 5;, the value of the num variable is 5.
• Assume its address is 120.
• The name num is just a symbol that refers to that address.

Symbol Table

• The symbol table maps variables and their addresses in memory.
• The num variable is stored at the 120 address.

Creating a Pointer

• Use int* p; to create a pointer.
• p = # stores the address of num in the pointer.*

Dereferencing

• Use *p to access the value of the variable through the pointer.
• cout << *p; displays the value at that address.

Address Operator

• & is used to get the address of a variable.
• Example: &num gets the address of num.

Size of Pointer

• The size of any type of pointer is usually 8 bytes.
• The size of a pointer depends on the system.

Pointer Operations

• Use *p += 1; to increment the pointed value.
• Pointers can be added and subtracted with other variables.*

Null Pointer

• A null pointer means it does not point to any valid memory.
• It should always be initialized.

Conclusion

• Pointers are essential for memory management and data access in C++.
• Students should learn to use pointers correctly.
• It is necessary to practice solving many problems using pointers.

Practice Questions

• What is a pointer?
• What is the dereference operator?
• Types of pointers and their uses.

These notes provide detailed information about pointers, which will assist students when programming in C++.