From 30d599ca44ebec5ec1b8022edd6d4c6592c2cf2f Mon Sep 17 00:00:00 2001
From: 3013050 <3013050@stud.hs-mannheim.de>
Date: Fri, 11 Oct 2024 01:54:22 +0200
Subject: [PATCH] Initial commit

---
 fakultaetsCalc.zig | 50 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 fakultaetsCalc.zig

diff --git a/fakultaetsCalc.zig b/fakultaetsCalc.zig
new file mode 100644
index 0000000..8d6e69b
--- /dev/null
+++ b/fakultaetsCalc.zig
@@ -0,0 +1,50 @@
+const std = @import("std");
+
+pub fn main() !void {
+    const reader = std.io.getStdIn().reader();
+    const writer = std.io.getStdOut().writer();
+
+    const userNumberInput: u128 = try getInputNumber(writer, reader);
+
+    const calcedFact = try calcFact(userNumberInput);
+
+    try writer.print("Calculated number: {d}\n", .{calcedFact});
+}
+
+pub fn getInputNumber(writer: anytype, reader: anytype) !u128 {
+    var buffer: [256]u8 = undefined;
+
+    while (true) {
+        try writer.print("Enter a number \n", .{});
+        try writer.print("> ", .{});
+        const amountInputBytes = try reader.read(&buffer);
+
+        const input_slice = buffer[0..(amountInputBytes - 1)];
+
+        const result = std.fmt.parseInt(u128, input_slice, 10) catch |err| {
+            switch (err) {
+                error.InvalidCharacter => {
+                    try writer.print("Error: Invalid character in input.\n", .{});
+                },
+                error.Overflow => {
+                    try writer.print("Error: Too large.\n", .{});
+                },
+            }
+            try writer.print("\n", .{});
+            continue;
+        };
+        return result;
+    }
+}
+
+pub fn calcFact(maxNum: u128) !u128 {
+    if (maxNum == 0) {
+        return 1;
+    }
+
+    const multValue: u128 = try calcFact(maxNum - 1);
+    return (maxNum * multValue);
+}
+
+// Bei start wird Zufallszahl gewählen
+// Nutzer sucht dann manuel mit binary search nach der zahl