modules

Modules and procedures

Simple module

Implement a module called math which defines mathematical constats pi (~ 3.1416...) and e (base of natural logarithm, e=exp(1) ~ 2.7183).

Utilize the module from a main program and print out the constants.

The program can be build as

gfortran -o math_test math.F90 main.F90

Module procedures

1. Add to your math module a function that takes as input the radius of circle and returns the area of the circle.

2. Add to your math module a subroutine that converts a polar coordinate representation (r, phi) into cartesian representation (x, y). Implement also a subroutine which does the reverse transformation. The formulas are:

   x = r * cos(phi), y = r * sin(phi), r² = x² + y², phi = atan2(y, x)