Binary Calculator (C++)

This repository contains a small C++ project that:

• Builds a binary expression tree representing arithmetic expressions in Reverse Polish Notation (RPN / postfix) or Binary Calculator - As you prefer.
• Evaluates the expression and prints the result to standard output.
• Provides basic error handling: invalid tokens, insufficient operands, division by zero.

Repository structure

rpn_calc_cpp/
├─ src/
│  ├─ main.cpp
│  ├─ expr_tree.cpp
├─ include/
│  ├─ expr_tree.h
├─ examples/
│  ├─ example1.txt
├─ CMakeLists.txt
├─ Makefile
├─ run_example.sh
├─ README.md
├─ LICENSE

Requirements

• A modern C++ compiler (recommended g++ >= 9 or clang++).
• CMake (optional) for building.

How to compile

With g++

g++ -std=c++17 src/main.cpp src/expr_tree.cpp -o calc

With Makefile

make

With CMake

mkdir -p build
cd build
cmake ..
cmake --build .

Usage

The program reads tokens provided as command-line arguments. Each token must be an integer (e.g., 3 or -12) or one of the operators + - * /.

Examples:

./calc 1 2 + 3 *
# output: 9

./calc 5 1 2 + 4 * + 3 -
# equivalent to: 5 + ((1+2)*4) - 3 = 14

Note: When using shell wildcards like *, the shell may expand them before passing to the program. To avoid shell expansion for the asterisk operator, quote or escape it:

./calc 1 2 + 3 '*'
# or
./calc 1 2 + 3 \*

The program uses integer arithmetic (long long) and performs integer division (truncation toward zero). If you prefer floating-point arithmetic, modify expr_tree.cpp or open an issue.

Getting started

1. Open src/main.cpp to see how command-line tokens are processed.
2. include/expr_tree.h and src/expr_tree.cpp implement the expression tree and evaluation.
3. Run make or compile directly with g++.
4. Test using the expressions in examples/ or create your own.

Useful links

• Reverse Polish notation (RPN): https://en.wikipedia.org/wiki/Reverse_Polish_notation
• Expression trees: https://en.wikipedia.org/wiki/Binary_expression_tree
• CMake tutorial: https://cmake.org/cmake/help/latest/guide/tutorial/index.html

License

MIT — see LICENSE.