Characters and Strings

CHRPAK is a FORTRAN90 library which handles characters and strings.

CHRPAK began when I simply wanted to be able to capitalize a string. Now it has expanded to a number of interesting uses. Many unusual situations are provided for, including

Many of the routine names begin with the name of the data type they operate on:


The computer code and data files made available on this web page are distributed under the GNU LGPL license.


CHRPAK is available in a C version and a C++ version and a FORTRAN77 version and a FORTRAN90 version and a MATLAB version and a Python version.

Related Software and Data:

CAESAR, a FORTRAN90 library which can apply a Caesar Shift Cipher to a string of text.

ROT13, a FORTRAN90 library which can encipher a string using the ROT13 cipher for letters, and the ROT5 cipher for digits.

Source Code:

Examples and Tests:

List of Routines:

You can go up one level to the FORTRAN90 source codes.

Last revised on 30 January 2016.