mirror of
https://github.com/ratfactor/ziglings
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45 lines
1.6 KiB
Zig
45 lines
1.6 KiB
Zig
//
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// For loops also let you use the "index" of the iteration, a number
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// that counts up with each iteration. To access the index of iteration,
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// specify a second condition as well as a second capture value.
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//
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// for (items, 0..) |item, index| {
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//
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// // Do something with item and index
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//
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// }
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//
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// You can name "item" and "index" anything you want. "i" is a popular
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// shortening of "index". The item name is often the singular form of
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// the items you're looping through.
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//
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const std = @import("std");
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pub fn main() void {
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// Let's store the bits of binary number 1101 in
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// 'little-endian' order (least significant byte or bit first):
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const bits = [_]u8{ 1, 0, 1, 1 };
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var value: u32 = 0;
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// Now we'll convert the binary bits to a number value by adding
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// the value of the place as a power of two for each bit.
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//
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// See if you can figure out the missing pieces:
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for (bits, ???) |bit, ???| {
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// Note that we convert the usize i to a u32 with
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// @intCast(), a builtin function just like @import().
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// We'll learn about these properly in a later exercise.
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const i_u32: u32 = @intCast(i);
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const place_value = std.math.pow(u32, 2, i_u32);
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value += place_value * bit;
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}
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std.debug.print("The value of bits '1101': {}.\n", .{value});
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}
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//
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// As mentioned in the previous exercise, 'for' loops have gained
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// additional flexibility since these early exercises were
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// written. As we'll see in later exercises, the above syntax for
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// capturing the index is part of a more general ability. Hang in
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// there!
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