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Lecture 10, Mon 05/04
The good, bad and ugly about pointers, C++ Memory Model, Dynamic memory allocation (Heap), Heap vs Stack
Lecture Video
I went the full time today, so I’ll make it up to you with a shorter video either on Wednesday or next Monday!
Topics
The good:
- Pointers allow arrays to be passed to functions efficiently
- Pointers allow arrays of large structs to be traversed effiently
The bad:
- Pointers can only point to one type of data (not generic)
- They don’t automatically point - need to do some work
The ugly
- Bugs in code that involves pointers can cause your program to irrecoverably crash (Segmentation fault)
- Examples: dereferencing a null pointer, out of bound array access, dereferncing a pointer that has junk value.
C++ Memory model
- Barebones model of memory: value vs address
- Scope: local vs. global
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Layout of compiled C++ program in memory: text, global data , heap and stack
- A first look at dynamic memory allocation
- The hows and whys of creating data on the stack vs. heap