Pointers and memory Ch 9 & 13.1 Highlights - new & delete - PowerPoint PPT Presentation

Jul 01, 2023 •369 likes •514 views

Pointers and memory Ch 9 & 13.1 Highlights - new & delete Pointers A pointer is used to store a memory address and denoted by a * (star!) Here variable xp is a integer pointer The * goes from address to variable (much like when you

Pointers and memory Ch 9 & 13.1
Highlights - new & delete
Pointers A pointer is used to store a memory address and denoted by a * (star!) Here variable xp is a integer pointer The * goes from address to variable (much like when you hit ENTER on a url) (See last time: pointerBasics.cpp)
Boxes What is comes next in this pattern? Basic programming: Ask for one box with a name Intermediate programming: Ask for multiple boxes with one name Advanced programming: ??? ???
Boxes What is comes next in this pattern? Basic programming: Ask for one box with a name Intermediate programming: Ask for multiple boxes with one name Advanced programming: Ask for a box without giving it a name
new Pointers are also especially useful to use with the new command The new command will create a variable (box) of the type you want ask for box The new integer has no separate name, just part of xp (as array boxes part of array name) (See: newMemory.cpp)
new What does this do?
new What does this do? Asking for a lot of boxes there... (See: memoryLeak.cpp)
delete When your program exits, the operating system will clean up your memory If you want to clean up your memory while the program is running, use delete command (See: deleteMemory.cpp)
delete As you can manage how you want to create new variables/boxes, using new/delete is called dynamic memory Before, the computer took care of memory by creating variables/boxes when you use a type then deleting when the function ends Before Now
delete This is also a memory leak: By the 3 rd line, there is no link back to the box on the 2 nd line (dangling pointer) There should be a “delete” for every “new”
delete Memory management is a hard part of C++ You need to ensure you delete all your boxes after you are done with them, but before the pointer falls out of scope (see: lostPointer.cpp) Some other languages manage memory for you
Person class The ability to have non-named boxes allows you to more easily initialize pointers (See: personV3.cpp)
Pointer to pointer You can have multiple stars next to types: Each star indicates how many arrows you need to follow before you find the variable int*** int** int* int 8 x (See: pointerPointers.cpp)

Recommend

Pointers and Dynamic Memory Allocation Pointers 2 Pointers Pointer-type variables allow

Pointers and Dynamic Memory Allocation Pointers 2 Pointers Pointer-type variables allow accessing memory in an indirect way. Memory Memory a a p int a; int a; int *p; a=10; p=&a; *p=10; 3 Operators * and &

325 views • 17 slides

CS162 - POINTERS Lecture: Pointers and Dynamic Memory What are pointers Why dynamically

CS162 - POINTERS Lecture: Pointers and Dynamic Memory What are pointers Why dynamically allocate memory How to dynamically allocate memory What about deallocation? Walk thru pointer exercises CS162 Pointers 1 CS162 -

477 views • 27 slides

Pointers and dynamic objects Topics Pointers Memory addresses Declaration

Pointers and dynamic objects Topics Pointers Memory addresses Declaration Dereferencing a pointer Pointers to pointer Static vs. dynamic objects new and delete Computer Memory Each variable is assigned a memory

636 views • 48 slides

Pointers & Dynamic Memory Review C Pointers Introduce C++ Pointers Data Abstractions

Pointers & Dynamic Memory Review C Pointers Introduce C++ Pointers Data Abstractions CSCI-2320 Dr. Tom Hicks Computer Science Department 2 Printing! Use Computer Science Printers Only For Your Computer Science Homework!!!! Print

1.19k views • 37 slides

Pointers Eric McCreath Introduction Pointers in c are basically memory addresses, they provide a

Pointers Eric McCreath Introduction Pointers in c are basically memory addresses, they provide a simple and flexible way of your program referencing data. All parameters in C are passed by making copies of the arguments to the function call.

271 views • 7 slides

Pointers Pointers are integer values that refer to addresses in memory scanf(

Pointers Pointers are integer values that refer to addresses in memory scanf( "%d", &v ); address of operator Principles of Computer Science II Nadeem Abdul Hamid int * ==> pointer to int type CSC121A -

905 views • 3 slides

Pointers Ch 9 & 13.1 Highlights - pointers - dynamic arrays - new & delete object vs

Pointers Ch 9 & 13.1 Highlights - pointers - dynamic arrays - new & delete object vs memory address An object is simply a box in memory and if you pass this into a function it makes a copy A memory address is where a box is located

457 views • 41 slides

Dangling Pointers Periklis Akritidis --2010 Use-after-free Vulnerabilities Accessing Memory

Cling: A Memory Allocator to Mitigate Dangling Pointers Periklis Akritidis --2010 Use-after-free Vulnerabilities Accessing Memory Through Dangling Pointers Techniques : Heap Spraying, Feng Shui Manual memory management is error prone

574 views • 35 slides

Topic 7 1. Defining and using pointers 2. Arrays and pointers 3. C and C++ strings 4.

Topic 7 1. Defining and using pointers 2. Arrays and pointers 3. C and C++ strings 4. Dynamic memory allocation 5. Arrays and vectors of pointers 6. Problem solving: draw a picture 7. Classes of objects 8. Pointers and objects

613 views • 21 slides

Before we begin Any questions? Function Pointers Recall: Program Memory Function pointers

Before we begin Any questions? Function Pointers Recall: Program Memory Function pointers The memory used by a program is generally Provides access to executable code section. separated into the following sections: Function

669 views • 7 slides

Pointers and Arrays Pointers and Arrays We've seen examples of both of these in our LC-3

Chapter 16 Pointers and Arrays Pointers and Arrays We've seen examples of both of these in our LC-3 programs; now we'll see them in C. Pointer Address of a variable in memory Allows us to indirectly access variables in other words,

1.1k views • 29 slides

Data, memory, pointer Pointers and arrays 1-1 Data, memory memory address: every byte

Data, memory, pointer Pointers and arrays 1-1 Data, memory memory address: every byte is identified by a numeric address in the memory. once a variable is defined , one cannot predict its memory address, entirely determined by

976 views • 70 slides

Pointers Ch 9 & 13.1 Highlights - pointers object vs memory address An object is simply a

Pointers Ch 9 & 13.1 Highlights - pointers object vs memory address An object is simply a box in memory and if you pass this into a function it makes a copy A memory address is where a box is located and if you pass this into a function,

471 views • 17 slides

Fundamentals of Programming Lecture 15 Hamed Rasifard 1 Outline Types of Pointers

Fundamentals of Programming Lecture 15 Hamed Rasifard 1 Outline Types of Pointers Arrays of Pointers Multiple Indirection Initializing Pointers Pointers to Functions Dynamic Memory Allocation 2 Types of Pointers

199 views • 19 slides

Pointers about pointers Announcements Midterm next week pointer is a memory address

Pointers about pointers Announcements Midterm next week pointer is a memory address Material covered up until June 18 (last week, is 4 bytes like an unsigned int signals) can address up to 2^32 bytes = 4 gb Allowed to have

321 views • 10 slides

Function Pointers Refined Memory Model 1 The C0 Memory Model so far Local Memory Allocated

Function Pointers Refined Memory Model 1 The C0 Memory Model so far Local Memory Allocated Memory Two memories main A apple 20 Local memory H o one frame per function call 5 3 pumpkin 10 o frame contains hdict_lookup

691 views • 25 slides

Memory & C Pointers Yunhao Zhang Cornell University What is memory? cooling fan CPU under

Memory & C Pointers Yunhao Zhang Cornell University What is memory? cooling fan CPU under the cooling fan Memory * Images from https://www.123rf.com/ What is memory? Circuits connecting CPU and memory * Images from

336 views • 18 slides

Chapter 16 Pointers and Arrays Pointers and Arrays We've seen examples of both of these in our

Chapter 16 Pointers and Arrays Pointers and Arrays We've seen examples of both of these in our C programs; now we'll see how they are implemented in LC-3. Pointer Address of a variable in memory Allows us to indirectly access

343 views • 16 slides

Pointers to Functions C doesn t require that pointers point only to data; it s also

Pointers to Functions C doesn t require that pointers point only to data; it s also possible to have pointers to functions. Pointers to Functions Function pointers point to memory addresses where functions are stored. o int (*fp)

240 views • 5 slides

Pointers and Memory 1 Pointer values Pointer values are memory addresses

Pointers and Memory 1 Pointer values Pointer values are memory addresses Think of them as a kind of integer values The first byte of memory is 0, the next 1, and so on A pointer p can hold the address of a memory

1.01k views • 31 slides

Contiguous chunks of memory Arrays/strings: pointers and memory allocation int * a = new

Contiguous chunks of memory Arrays/strings: pointers and memory allocation int * a = new int[100]; Why not rely solely on string and vector classes? In C++ allocate using array form of new how are string and vector implemented? 0

196 views • 3 slides

TOS Arno Puder 1 Objectives Learn how to read and write from memory using C-pointers

TOS Arno Puder 1 Objectives Learn how to read and write from memory using C-pointers Implement the very first TOS functions 2 Memory Access Memory often needs to be manipulated manually. Two operations: - Peek: peek (i.e.

380 views • 25 slides

Personal SE Computer Memory Addresses C Pointers Computer Memory Organization Memory is a

Personal SE Computer Memory Addresses C Pointers Computer Memory Organization Memory is a bucket of bytes . Computer Memory Organization Memory is a bucket of bytes. Each byte is 8 bits wide. Computer Memory Organization Memory

994 views • 42 slides

Programming for Engineers Pointers ICEN 200 Spring 2018 Prof. Dola Saha 1 Pointers

Programming for Engineers Pointers ICEN 200 Spring 2018 Prof. Dola Saha 1 Pointers Pointers are variables whose values are memory addresses . A variable name directly references a value, and a pointer indirectly references a value.

738 views • 28 slides