rCalc

rCalc is a simple calculator created as a hobby project to improve my C programming language knowledge and GUI creation skills. GTK3 toolkit is used to create the GUI.

Features

Support the basic arithmetic operations and can calculate the square root and the power of a number.
Parentheses are supported.
Digital keyboard is supported (enter key can be used to display the result).
Wrong and malformed expressions are handled with error messages.
White spaces are recognized.
Error-free expressions are saved into the internal history.
Support deleting any character before the cursor's current position by pressing "⟲" button.
Display can be cleared by clicking on "C" button.

How to build

1) Build using Make

Download and install GTK3 Packages. Download and install GNU Make if it is not installed. Then change directory to downloaded repository and then type:

$ make

To remove the compiled files (which can be found in the obj/ directory) and the executable, just type:

$ make clean

2) Build manually

Download and install GTK3 Packages. Then change directory to downloaded repository and type:

$ gcc -o rCalc ./src/calc.c ./src/stack.c ./src/callbacks.c ./src/main.c -std=c99 -g3 -Wall -I./include `pkg-config --cflags --libs gtk+-3.0` -lm

And then execute rCalc:

$ ./rCalc

Note 1 : The compiled files (.o) will not be created when building manually.
Note 2 : Due to my decision to write the calculator only in plain C, I ignored the warning messages about using deprecated functions.

Usage

rCalc works like any calculator, it follows rules of operator precedence.

The minus sign '-' is unary, that is, to calculate a substraction, you MUST use parentheses for the number that is after the minus sign.

For example, to calculate 3.141-2.718, typing 3.141-2.718 is wrong, but 3.141-(2.718) or 3.141+(-2.718) gives a true result. 3-(sqrt(9)) gives syntax error while 3-sqrt(9) doesn't.

The multiplication sign '*' cannot be omitted. 3.141(2.718) or (3.141)(2.718) gives syntax error.

To display the precedent operation, click on the "⟲" button (the entry must be empty).