Add basic Input validation for if user enters digit or 'q' as a choice

.gitignore

@@ -14,3 +14,8 @@ Cargo.lock
 # MSVC Windows builds of rustc generate these, which store debugging information
 *.pdb
 
+
+
+# Added by cargo
+
+/target

Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "math-tool"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

src/main.rs

@@ -0,0 +1,51 @@
+/*
+Written by: James Musselman
+On: 3/14/2024
+Updated: Never
+Description:
+    This tool was writen as part of my 100DaysOfCode commitment for the 2024 year to help establish a
+    habit of programming daily and fuel my continious drive to learn.
+
+    The tool below should allow the user to run basic, intermediate, and advanced math computations.
+    The user will select the equation or type of math they want to be done, enter the data, and
+    then recive the result of the computation.
+
+    Future work could include showing how the answer was calculated, showing graphs, and exporting to
+    a text file.
+
+*/
+use std::io;
+
+
+fn main() {
+    // TODO: Greet and explain tool
+
+    // Get user choice on what they want to use
+    loop {
+        let mut user_input = String::new();
+
+        println!("Please select a function below or use 'q' to quit:");
+
+        io::stdin().read_line(&mut user_input)
+            .expect("Failed to read line");
+
+        if user_input.trim().eq_ignore_ascii_case("q") {
+            break;
+        }
+
+        let num: Result<i32, _> = user_input.trim().parse();
+
+        // Match statement to run choice
+        match num {
+            Ok(num) => {
+                run_function(num);               
+            } 
+            Err(_) => println!("Invalid input. Please try again."),
+        }
+    }
+}
+
+fn run_function(num: i32) {
+// run choice, then ask again or quit if the user selects that option
+println!("{}",num)
+}