mirror of
https://codeberg.org/andyscott/ziglings.git
synced 2024-09-19 11:28:08 -04:00
e9e6be4e05
This is in preparation for another dive into 'for' in an upcoming Exercise 100. Also reformatted 095 for 65 columns and some wording.
43 lines
1.5 KiB
Zig
43 lines
1.5 KiB
Zig
//
|
|
// For loops also let you use the "index" of the iteration, a number
|
|
// that counts up with each iteration. To access the index of iteration,
|
|
// specify a second condition as well as a second capture value.
|
|
//
|
|
// for (items, 0..) |item, index| {
|
|
//
|
|
// // Do something with item and index
|
|
//
|
|
// }
|
|
//
|
|
// You can name "item" and "index" anything you want. "i" is a popular
|
|
// shortening of "index". The item name is often the singular form of
|
|
// the items you're looping through.
|
|
//
|
|
const std = @import("std");
|
|
|
|
pub fn main() void {
|
|
// Let's store the bits of binary number 1101 in
|
|
// 'little-endian' order (least significant byte first):
|
|
const bits = [_]u8{ 1, 0, 1, 1 };
|
|
var value: u32 = 0;
|
|
|
|
// Now we'll convert the binary bits to a number value by adding
|
|
// the value of the place as a power of two for each bit.
|
|
//
|
|
// See if you can figure out the missing pieces:
|
|
for (bits, ???) |bit, ???| {
|
|
// Note that we convert the usize i to a u32 with
|
|
// @intCast(), a builtin function just like @import().
|
|
// We'll learn about these properly in a later exercise.
|
|
var place_value = std.math.pow(u32, 2, @intCast(u32, i));
|
|
value += place_value * bit;
|
|
}
|
|
|
|
std.debug.print("The value of bits '1101': {}.\n", .{value});
|
|
}
|
|
//
|
|
// As mentioned in the previous exercise, 'for' loops have gained
|
|
// additional flexibility since these early exercises were
|
|
// written. As we'll see in later exercises, the above syntax for
|
|
// capturing the index is part of a more general ability. hang in
|
|
// there!
|