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const std = @import("std");
const expect = std.testing.expect;
const mem = std.mem;
const fmt = std.fmt;
test "using slices for strings" {
// Zig has no concept of strings. String literals are const pointers
// to null-terminated arrays of u8, and by convention parameters
// that are "strings" are expected to be UTF-8 encoded slices of u8.
// Here we coerce *const [5:0]u8 and *const [6:0]u8 to []const u8
const hello: []const u8 = "hello";
const world: []const u8 = "世界";
var all_together: [100]u8 = undefined;
// You can use slice syntax with at least one runtime-known index on an
// array to convert an array into a slice.
var start: usize = 0;
_ = &start;
const all_together_slice = all_together[start..];
// String concatenation example.
const hello_world = try fmt.bufPrint(all_together_slice, "{s} {s}", .{ hello, world });
// Generally, you can use UTF-8 and not worry about whether something is a
// string. If you don't need to deal with individual characters, no need
// to decode.
try expect(mem.eql(u8, hello_world, "hello 世界"));
}
test "slice pointer" {
var array: [10]u8 = undefined;
const ptr = &array;
try expect(@TypeOf(ptr) == *[10]u8);
// A pointer to an array can be sliced just like an array:
var start: usize = 0;
var end: usize = 5;
_ = .{ &start, &end };
const slice = ptr[start..end];
// The slice is mutable because we sliced a mutable pointer.
try expect(@TypeOf(slice) == []u8);
slice[2] = 3;
try expect(array[2] == 3);
// Again, slicing with comptime-known indexes will produce another pointer
// to an array:
const ptr2 = slice[2..3];
try expect(ptr2.len == 1);
try expect(ptr2[0] == 3);
try expect(@TypeOf(ptr2) == *[1]u8);
}
// test
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