ECalc - a GUI calculator

Main features:

• Evaluation of (complex) expressions (see the Eval library). The expressions are typed in, as in the most programming language.
• Handling of variables (of different types, like integers, double, complexes, points, strings and arrays and matrices of them).
• The one and two dimensional arrays (matrices) can be handled in tables, too - this is somewhat similar to the well known spearsheets (with homogenous item type).
• Assigment of charts to the arrays: the array items are shown graphically (as bar- or piecharts). The point is that these charts follow the changes of the array items.
• Automatic assigment of the variables: in this case the value of the variable is always recalculated, according to the previously specified expression ("derived values").
• Sliders: the (scalar) variable values (integers, doubles) can be set with scrollbars, too. The scrollbars are assigned to a variable and a given value range where the value can be set.
  This is mostly useful in studying the changes of relatively complex derived values.
• Graphical visualization of the expressions. They can be displayed as functions, or in a form that is more human-readable than the one line expression (mostly for complex/long expressions).
• Visualization of parameterized functions (with two dependent variables, displayed in two dimension).
• Symbolic (partial) derivation of the expressions. The partial derivation variable can be selected (it doesn't always need to be usual "x").
  Numerical integration is also possible. There are standard Eval functions for these operations.
• Extensive help, based on the ATX document subsystem.
• There is no installation process (except one additional step), just extract the downloaded package.
• The program settings (open windows, history, variables, etc) are stored in a ini file, in the same directory with the executable.
  The additional step is that you have to set the CHDIR environment variable to the directory, where the package has been extracted to (the program runs properly without this, only the texts on the graphics will be missing).
• Multilanguage interface, available from the main window's system menu.

Download the program.

Screenshots: