first commitHEADmain

6 files changed, 284 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
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+++ b/.gitignore
@@ -0,0 +1 @@
+/target
diff --git a/Cargo.lock b/Cargo.lock
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+++ b/Cargo.lock
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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "simple-calculator"
+version = "0.1.0"
diff --git a/Cargo.toml b/Cargo.toml
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+++ b/Cargo.toml
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+[package]
+name = "simple-calculator"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
diff --git a/LICENSE b/LICENSE
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+++ b/LICENSE
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+MIT License
+
+Copyright (c) 2025 tyropro
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/README.md b/README.md
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+++ b/README.md
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+# Calculator
+
+This is a very simple calculator programmed in Rust.
+
+It takes in a string infix input and converts it to a postfix expression before evaluating it.
+
+# TODO
+
+-   [x] Get it working
+-   [x] Unary and binary subtraction
+-   [ ] Handle user input error
diff --git a/src/main.rs b/src/main.rs
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+++ b/src/main.rs
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+#[derive(PartialEq, Clone, Copy, Debug)]
+enum Token {
+    Number(f64),
+    Addition,
+    // UnarySubtraction,
+    Subtraction,
+    Multiplication,
+    Division,
+    LeftParenthesis,
+    RightParenthesis,
+    Index,
+}
+
+impl Token {
+    fn into_float(self) -> Option<f64> {
+        match self {
+            Self::Number(s) => Some(s),
+            _ => None,
+        }
+    }
+}
+
+fn tokenisation(input: &str) -> Result<Vec<Token>, ()> {
+    let chars = input.chars();
+
+    let mut tokens = Vec::new();
+    let mut token_buffer = Vec::new();
+
+    let mut unary_sub = true;
+
+    for token in chars {
+        if token.is_numeric() {
+            token_buffer.push(token);
+            unary_sub = false;
+            continue;
+        }
+
+        if token.is_ascii_punctuation() && token_buffer.len() > 0 {
+            let stringified_token = token_buffer.iter().collect::<String>();
+            let numerical_token = stringified_token.as_str().parse::<f64>().unwrap();
+            tokens.push(Token::Number(numerical_token));
+            token_buffer.clear();
+        }
+
+        if token == '+' {
+            tokens.push(Token::Addition);
+        } else if token == '-' {
+            if unary_sub {
+                token_buffer.push(token);
+            } else {
+                tokens.push(Token::Subtraction);
+            }
+        } else if token == '*' {
+            tokens.push(Token::Multiplication);
+        } else if token == '/' {
+            tokens.push(Token::Division);
+        } else if token == '(' {
+            tokens.push(Token::LeftParenthesis);
+        } else if token == ')' {
+            tokens.push(Token::RightParenthesis);
+        } else if token == '^' {
+            tokens.push(Token::Index);
+        } else if token == ' ' {
+            continue;
+        } else {
+            println!(
+                "WARN: cannot use '{}' in expressions. Character has been ignored.",
+                token
+            );
+            continue;
+        }
+
+        unary_sub = true;
+    }
+
+    if token_buffer.len() > 0 {
+        let stringified_token = token_buffer.iter().collect::<String>();
+        let numerical_token = stringified_token.as_str().parse::<f64>().unwrap();
+        tokens.push(Token::Number(numerical_token));
+        token_buffer.clear();
+    }
+
+    if tokens.len() < 1 {
+        return Err(());
+    }
+
+    Ok(tokens)
+}
+
+fn shunting_yard(infix: Vec<Token>) -> Result<Vec<Token>, ()> {
+    let mut output: Vec<Token> = Vec::new();
+    let mut stack: Vec<Token> = Vec::new();
+
+    for token in infix {
+        // dbg!(&token);
+        match token {
+            Token::Number(_) => output.push(token),
+            Token::Addition | Token::Subtraction => {
+                if stack.len() > 0 {
+                    if stack[0] == Token::Index
+                        || stack[0] == Token::Multiplication
+                        || stack[0] == Token::Division
+                    {
+                        while stack[0] == Token::Index
+                            || stack[0] == Token::Multiplication
+                            || stack[0] == Token::Division
+                            || stack[0] == Token::Addition
+                            || stack[0] == Token::Subtraction
+                        {
+                            output.push(stack[0]);
+                            stack.remove(0);
+
+                            if stack.len() == 0 {
+                                break;
+                            }
+                        }
+                    }
+                }
+                stack.insert(0, token)
+            }
+            Token::Multiplication | Token::Division => {
+                if stack.len() > 0 {
+                    if stack[0] == Token::Index {
+                        while stack[0] == Token::Index
+                            || stack[0] == Token::Multiplication
+                            || stack[0] == Token::Division
+                        {
+                            output.push(stack[0]);
+                            stack.remove(0);
+
+                            if stack.len() == 0 {
+                                break;
+                            }
+                        }
+                    }
+                }
+                stack.insert(0, token);
+            }
+            Token::RightParenthesis => {
+                if stack.len() > 0 {
+                    while stack[0] != Token::LeftParenthesis {
+                        output.push(stack[0]);
+                        stack.remove(0);
+                    }
+                    stack.remove(0);
+                }
+            }
+            _ => stack.insert(0, token),
+        }
+
+        // dbg!(&output);
+    }
+
+    for token in stack {
+        if token == Token::LeftParenthesis {
+            return Err(());
+        }
+        output.push(token);
+    }
+
+    Ok(output)
+}
+
+fn calculate(mut input: Vec<Token>) -> f64 {
+    // let mut input = postfix;
+    let mut stack = Vec::new();
+
+    while input.len() > 0 {
+        match input[0] {
+            Token::Number(_) => {
+                stack.insert(0, input[0]);
+            }
+            Token::Addition => {
+                let a = stack[1].into_float().unwrap();
+                let b = stack[0].into_float().unwrap();
+                stack[0] = Token::Number(a + b);
+                stack.remove(1);
+            }
+            Token::Subtraction => {
+                let a = stack[1].into_float().unwrap();
+                let b = stack[0].into_float().unwrap();
+                stack[0] = Token::Number(a - b);
+                stack.remove(1);
+            }
+            Token::Multiplication => {
+                let a = stack[1].into_float().unwrap();
+                let b = stack[0].into_float().unwrap();
+                stack[0] = Token::Number(a * b);
+                stack.remove(1);
+            }
+            Token::Division => {
+                let a = stack[1].into_float().unwrap();
+                let b = stack[0].into_float().unwrap();
+                stack[0] = Token::Number(a / b);
+                stack.remove(1);
+            }
+            Token::Index => {
+                let a = stack[1].into_float().unwrap();
+                let b = stack[0].into_float().unwrap();
+                stack[0] = Token::Number(a.powf(b));
+                stack.remove(1);
+            }
+            _ => {}
+        }
+
+        input.remove(0);
+    }
+
+    stack[0].into_float().unwrap()
+}
+
+fn main() {
+    loop {
+        let mut input = String::new();
+        std::io::stdin().read_line(&mut input).unwrap();
+        let calculation = input.trim();
+
+        if calculation.to_lowercase() == "quit" || calculation.to_lowercase() == "exit" {
+            break;
+        }
+
+        let infix_vector = tokenisation(calculation);
+        if infix_vector.is_err() {
+            println!("ERR: Invalid expression.\n");
+            continue;
+        }
+
+        let postfix_vector = shunting_yard(infix_vector.unwrap());
+        if postfix_vector.is_err() {
+            println!("ERR: Invalid expression.\n");
+            continue;
+        }
+
+        let answer = calculate(postfix_vector.unwrap());
+
+        println!("{}\n", answer);
+    }
+}