# Exercises

### Exercises

This section closes the chapter. The exercises are small programs. Write them by hand. Compile them. Change them. Run them again.

Exercise 6-1. Declare an array of 10 integers and print the elements in order.

Exercise 6-2. Print the same array in reverse order.

Exercise 6-3. Write a function named `zero5` that takes `*[5]i32` and sets all five elements to zero.

Exercise 6-4. Copy one array to another. Change the second array. Print both arrays to show that the copy is separate.

Exercise 6-5. Declare this array with an inferred length:

```zig
const nums = [_]i32{ 1, 2, 3, 4, 5 };
```

Print its length.

Exercise 6-6. Create an array of 16 zero bytes using `**`.

Exercise 6-7. Create a 3 by 3 table of integers. Print the value in row 2, column 1.

Exercise 6-8. Write a function `sum` that takes `[]const i32` and returns the sum.

Exercise 6-9. Write a function `fill` that takes `[]i32` and an `i32` value, and sets every element of the slice to that value.

Exercise 6-10. Create an array of 8 integers. Make a slice containing elements 2 through 5. Change the slice. Print the original array.

Exercise 6-11. Declare a sentinel array:

```zig
const word: [5:0]u8 = .{ 'h', 'e', 'l', 'l', 'o' };
```

Convert it to `[:0]const u8` and print it with `{s}`.

Exercise 6-12. Print every byte of `"zig"` as a decimal number.

Exercise 6-13. Print every byte of `"é"` as a hexadecimal number.

Exercise 6-14. Use `std.unicode.Utf8View` to print the code points of `"hé"`.

Exercise 6-15. Write a function `countCodepoints` that takes `[]const u8` and returns `!usize`.

Exercise 6-16. Explain, in one sentence, the difference between `[N]T` and `[]T`.

Exercise 6-17. Explain, in one sentence, why `s.len` is not always the number of characters in a string.

Exercise 6-18. Write a program that accepts one string literal, prints its byte length, then prints its UTF-8 code point count.