program star
implicit none
real (kind=8) :: x
integer :: i
dt=0.001
pi=4*(atan1.0)
do i=1, Nsteps
t = n*dt
!calculate acceleration
ax=
ay=...
!calculate values at next step
vy=vy+ay*dt
vx=vx+ax*dt
x=x+vx*dt
y=y+vy*dt
end do
print *, "vx= ", vx
end program starFortran 90 is a high-level programming language commonly used in scientific and engineering applications. It was developed in the 1990s as an updated version of the original Fortran language, and it includes features such as modules, pointers, and free-form source code formatting.
A machine problem in Fortran 90 refers to a programming task or assignment that requires the use of the Fortran 90 language. This could include writing a program to solve a specific mathematical problem, creating a simulation, or implementing a particular algorithm.
In Fortran 90, variables are declared using the INTEGER, REAL, DOUBLE PRECISION, or CHARACTER keywords, followed by the variable name and an optional list of dimensions. For example, INTEGER :: x(3) would declare the variable x as an array of three integers.
DO and DO WHILE loops in Fortran 90?In Fortran 90, DO and DO WHILE loops are both used for repetitive tasks. The main difference is that DO loops have a fixed number of iterations, while DO WHILE loops continue as long as a specified condition is true. For example, DO i=1,10 would execute the loop 10 times, while DO WHILE (x < 100) would continue until the value of x is no longer less than 100.
Fortran 90 has built-in functions for reading and writing data files, such as READ and WRITE. These functions use formatted I/O to specify the format of the data being read or written. Additionally, Fortran 90 also has the OPEN statement for opening files and the CLOSE statement for closing files after use.