blob: 359a2f1b42f8bab5226eb762ecce02885692521c (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
|
//
// Now let's use pointers to do something we haven't been
// able to do before: pass a value by reference to a function.
//
// Why would we wish to pass a pointer to an integer variable
// rather than the integer value itself? Because then we are
// allowed to *change* the value of the variable!
//
// +-----------------------------------------------+
// | Pass by reference when you want to change the |
// | pointed-to value. Otherwise, pass the value. |
// +-----------------------------------------------+
//
const std = @import("std");
pub fn main() void {
var num: u8 = 1;
var more_nums = [_]u8{ 1, 1, 1, 1 };
// Let's pass a reference to num to our function and print it:
makeFive(&num);
std.debug.print("num: {}, ", .{num});
// Now something interesting. Let's pass a reference to a
// specific array value:
makeFive(&more_nums[2]);
// And print the array:
std.debug.print("more_nums: ", .{});
for (more_nums) |n| {
std.debug.print("{} ", .{n});
}
std.debug.print("\n", .{});
}
// This function should take a reference to a u8 value and set it
// to 5.
fn makeFive(x: *u8) void {
??? = 5; // fix me!
}
|
