Topic outline
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In this unit, students will cultivate a deeper understanding of how variables are declared and represented in memory. Students will also learn about pointers and how they can be used to reference certain memory locations.
Completing this unit should take approximately 4 hours.
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Students mustMark as done
Although this is not a language course, you should review these concepts, since an understanding this material is required before studying memory pointers. As described here:
"In the C programming language, data types are declarations for memory locations or variables that determine the characteristics of the data that may be stored and the methods (operations) of processing that are permitted involving them."
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Students mustMark as done
Read this article. As it explains:
"In computing, a word is the natural unit of data used by a particular processor design. A word is a fixed-sized piece of data handled as a unit by the instruction set or the hardware of the processor. The number of bits in a word (the word size, word width, or word length) is an important characteristic of any specific processor design or computer architecture."
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Students mustMark as done
We touched on pointers earlier; this video reviews that material. Watch from 35:51 until the end.
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Students mustMark as doneThis video expands on the discussion of pointers presented earlier in this unit.
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Students mustMark as done
This article discusses scalar, vector, and function pointers. Scalars occupy varying amounts of memory. For instance, an integer may occupy four bytes and a double may occupy eight bytes. Some compilers allow for extensions, such as long int and long double. These increase the memory occupied by that type of variable, and the value's accuracy and/or numeric range. You can also use different compilers on the same machine, and the same compiler may behave differently on different machines. Always check the compiler's documentation relative to your machine. In any case, a pointer incremented by 1, for instance, will always point to the next cell of a vector or array of that pointer's type.
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Students mustMark as done
Read this section on matrices. It shows how what we learned about pointers for vectors applies to building arrays. Essentially, we are building vectors of vectors. In the C/C++ sense, the first dimension points to the rows and the second dimension points to columns for a particular row. You will note that the vector of row pointers exists in contiguous memory, and that the columns for each individual row also exists in contiguous memory. However, it is not true that the array, as a whole, exists in contiguous memory. Thus, it is not possible to calculate a single memory pointer to a particular [r][c] cell of the array.
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Students mustMark as done
Read these sections. Two-dimensional matrices are very common in computer programming. This article expands on the previous one by getting specific about 2D matrix pointer arithmetic. Generalize your understanding of pointer arithmetic and you will see how it applies to data stored in contiguous memory. For instance, if you declare a pointer to a byte (unsigned char) you can march your way through any object that exists in contiguous memory.
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Students mustMark as done
Work through these exercises to get some hands-on experience with pointers.
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Students mustViewReceive a grade
Take this assessment to see how well you understood this unit.
- This assessment does not count towards your grade. It is just for practice!
- You will see the correct answers when you submit your answers. Use this to help you study for the final exam!
- You can take this assessment as many times as you want, whenever you want.
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