Initial commit

src/main.zig

@@ -0,0 +1,73 @@
+const std = @import("std");
+
+pub fn main() !void {
+    var gpa: std.heap.DebugAllocator(.{}) = .init;
+    const allocator = gpa.allocator();
+    defer _ = gpa.deinit();
+
+    const input = try getInput("Please enter a number: ");
+
+    var primes = try getPrimes(input, allocator);
+    defer primes.deinit(allocator);
+
+    var stdout_buffer: [100]u8 = undefined;
+    var stdout = std.fs.File.stdout().writer(&stdout_buffer);
+    var output = &stdout.interface;
+
+    if (primes.items.len == 0) {
+        try output.writeAll("No prime numbers were found.\n");
+    } else {
+        try output.print("Displaying {d} prime numbers from 2 to {d}:\n", .{primes.items.len, primes.items[primes.items.len - 1]});
+        for (primes.items) |prime| {
+            try output.print("{d} ", .{prime});
+        }
+    }
+
+    try output.flush();
+}
+
+fn getInput(message: []const u8) !usize {
+    var stdout_buffer: [100]u8 = undefined;
+    var stdout = std.fs.File.stdout().writer(&stdout_buffer);
+    var output = &stdout.interface;
+
+    var stdin_buffer: [100]u8 = undefined;
+    var stdin = std.fs.File.stdin().reader(&stdin_buffer);
+
+    var line_buffer: [100]u8 = undefined;
+    var w: std.io.Writer = .fixed(&line_buffer);
+
+
+    while (true) {
+        try output.writeAll(message);
+        try output.flush();
+
+        const line_length = try stdin.interface.streamDelimiterLimit(&w, '\n', .unlimited);
+        const input_line = line_buffer[0..line_length];
+
+        const res = std.fmt.parseInt(usize, input_line, 10) catch {
+            continue;
+        };
+        return res;
+    }
+}
+
+fn getPrimes(max: usize, allocator: std.mem.Allocator) !std.ArrayList(usize) {
+    var primes: std.ArrayList(usize) = .empty;
+
+    for (2..max+1) |i| {
+        if (isPrime(i)) try primes.append(allocator, i);
+    }
+
+    return primes;
+}
+
+fn isPrime(n: usize) bool {
+    if (n < 2) return false;
+
+    for (2..n) |i| {
+        if (n % i == 0) return false;
+    }
+
+    return true;
+}