notes/education/software development/ECE1400/Chapter 8 Exercises.md

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?

Answer: 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.

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.

Answer:

bool weekend[] = {true, [1 ... 5] = false, true};

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.

   Here's what the array might look like, with each row representing one digit:

const int segments[10][7] = {{1, 1, 1, 1, 1, 1, 0}, ...};

I've given you the first row of the initializer, fill in the rest.

Answer:

const int segments[10][7] = {
		{1, 1, 1, 1, 1, 1, 0}, // 0
		{0, 1, 1, 0, 0, 0, 0}, // 1
		{1, 1, 0, 1, 1, 0, 1}, // 2
		{1, 1, 1, 1, 0, 0, 1}, // 3
		{0, 1, 1, 0, 0, 1, 0}, // 4
		{1, 0, 1, 1, 0, 1, 1}, // 5
		{1, 0, 1, 1, 1, 1, 1}, // 6
		{1, 1, 1, 0, 0, 0, 0}, // 7
		{1, 1, 1, 1, 1, 1, 1}, // 8
		{1, 1, 1, 1, 0, 1, 1}  // 9
	};

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:

omitted]

```c
char chess_board[8][8] = {
	{'r', 'n', 'b', 'q', 'k', 'b', 'n', 'r'},
	{'p', 'p', 'p', 'p', 'p', 'p', 'p', 'p'},
	{' ', '.', ' ', '.', ' ', '.', ' ', '.'},
	{'.', ' ', '.', ' ', '.', ' ', '.', ' '},
	{' ', '.', ' ', '.', ' ', '.', ' ', '.'},
	{'.', ' ', '.', ' ', '.', ' ', '.', ' '},
	{' ', '.', ' ', '.', ' ', '.', ' ', '.'},
	{'.', ' ', '.', ' ', '.', ' ', '.', ' '},
	{'P', 'P', 'P', 'P', 'P', 'P', 'P', 'P'},
	{'R', 'N', 'B', 'K', 'Q', 'B', 'N', 'R'},
};
```


> 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).

```c
char checker_board[8][8];
for (int row = 0; row < 8; row++) {
	for (int column = 0; column < 8; column++) {
		if ((column + row) % 2 == 0) {
			checker_board[row][column] = 'B';
		} else {
			checker_board[row][column] = 'R';
		}
	}
}
```