Data Structures and Pointers

Agenda

• Data Structures
• Pointers

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1.

Data Structures

Clumping stuff together

Data Structures

• A data structure in a programming language allows us to glue together different types and treat them as a single object
• Why do this?

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Data Structures

• Consider a car - it has:
• Tires
• Windows
• Steering wheel
• In our code we want to just have a single object for each car
• Operating on tires, we know that they belong to this car

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Data Structures

• In C++ use the struct keyword

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Data Structures

• In Python, there is no support for direct data structures
• Instead use classes
• Only have simplified classes for this course
• L12 Classes Python

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2.

Pointers

Pointers going to point

Pointers

• Variables are stored in computer memory
• A pointer is a special kind of variable that indicates memory locations
• Pointers exist naturally in C and C++
• Pointers can be mimicked in Python

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Why Use Pointers

• Efficiency
• Instead of large memory copies into functions have less expensive pointer copies
• Very important with algorithms and data structures
• Function variable modification
• Modify external data from within a function
• Can use global variables instead

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Pointers in Python

• Can store objects in arrays/lists and then use indices to the array as a pointer
• Keep the objects as None (Python) until assigned values
• More on the use of these faux pointers during data structures like trees

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Pointers in C++

• Pointers get types like other variables
• A pointer has an asterisk * in front of the variable name
• Using * in code finds the value of the pointer (at that memory location)
• Using & for a regular variable gets the address of the variable
• L12 Pointers in C++

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CREDITS

Special thanks to all the people who made and released these awesome resources for free:

• Presentation template by SlidesCarnival

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