Zig by Example: While

While loops can be used to repeat expressions.

 
const std = @import("std");
const print = std.debug.print;
 
pub fn main() !void {
    var a: usize = 0;
    var b: usize = 0;
    var c: usize = 0;
    var d: usize = 0;

The body of a while loop will repeatedly execute until the loop’s condition is no longer true.

 
    while (a < 2) {
        print("a: {}\n", .{a});
        a += 1;
    }

Continue expressions can be used to evaluate an expression after each execution of a while loop’s body.

 
    while (b < 2) : (b += 1) {
        print("b: {}\n", .{b});
    }

You can specify multiple continue expressions by using the { <expr1>; <expr2>; ... } syntax.

 
    while (c < 4) : ({
        c += 1;
        c += 1;
    }) {
        print("c: {}\n", .{c});
    }

To break out of a while loop, use the break keyword.

 
    while (true) {
        break;
    }

To jump to the next iteration of a while loop, use the continue keyword.

 
    while (true) : (d += 1) {
        if (d < 2) {
            print("d: {}\n", .{d});
            continue;
        }
 
        break;
    }
}
 
$ zig run while.zig
a: 0
a: 1
b: 0
b: 1
c: 0
c: 2
d: 0
d: 1

Next example: For.

by Jason Phan | source | license