56 lines
2.2 KiB
Markdown
56 lines
2.2 KiB
Markdown
> 1. We discussed using the expression `sizeof(a) / sizeof(a[0]` to calculate the number of elements in an array. The expression `sizeof(a) / sizeof(t)` where `t` is the type of `a`'s elements would also work, but it's considered an inferior technique. Why?
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Answer:
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Using the type of the array's first element means that if you change the type of an array, it won't break the code that calculates the number of elements.
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> 3. Write a declaration of an array named weekend containing seven `bool` values. Include an initialize that makes the first and last values `true`; all other values should be `false`.
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Answer:
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```c
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bool weekend[] = {true, [1 ... 5] = false, true};
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```
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> 5. Calculators, watches, and other electronic devices often rely on 7 segment displays for numerical output. To form a digit, such devices turn on some of the seven segments while leaving others off.
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>
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> Here's what the array might look like, with each row representing one digit:
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```c
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const int segments[10][7] = {{1, 1, 1, 1, 1, 1, 0}, ...};
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```
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> I've given you the first row of the initializer, fill in the rest.
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Answer:
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```c
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const int segments[10][7] = {
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{1, 1, 1, 1, 1, 1, 0}, // 0
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{0, 1, 1, 0, 0, 0, 0}, // 1
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{1, 1, 0, 1, 1, 0, 1}, // 2
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{1, 1, 1, 1, 0, 0, 1}, // 3
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{0, 1, 1, 0, 0, 1, 0}, // 4
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{1, 0, 1, 1, 0, 1, 1}, // 5
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{1, 0, 1, 1, 1, 1, 1}, // 6
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{1, 1, 1, 0, 0, 0, 0}, // 7
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{1, 1, 1, 1, 1, 1, 1}, // 8
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{1, 1, 1, 1, 0, 1, 1} // 9
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};
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```
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>10. Write a declaration for an 8x8 `char` array named `chess_board`. Include an initializer that puts the following data into the array, one character per array element:
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\[omitted]
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```c
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char chess_board[8][8] = {
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{'r', 'n', 'b', 'q', 'k', 'b', 'n', 'r'},
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{'p', 'p', 'p', 'p', 'p', 'p', 'p', 'p'},
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{' ', '.', ' ', '.', ' ', '.', ' ', '.'},
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{'.', ' ', '.', ' ', '.', ' ', '.', ' '},
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{' ', '.', ' ', '.', ' ', '.', ' ', '.'},
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{'.', ' ', '.', ' ', '.', ' ', '.', ' '},
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{' ', '.', ' ', '.', ' ', '.', ' ', '.'},
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{'.', ' ', '.', ' ', '.', ' ', '.', ' '},
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{'P', 'P', 'P', 'P', 'P', 'P', 'P', 'P'},
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{'R', 'N', 'B', 'K', 'Q', 'B', 'N', 'R'},
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};
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```
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> 11. Write a program fragment that declares an 8x8 `char` array named `checker_board` and then uses a loop to store the following data into the array (one character per array element). |