How to Use FORTRAN Do Loops for Solving Equations - Step by Step Guide"

[McAfee]

Hey guys,

I'm new to fortran and I'm having a slight problem. I put my code below as reference. I first set up a my known values. Then I used an equation to solve for v. After I solve for v I then computed c which involves v.

What I'm now trying to do is to loop the value I got for c back into the equation [c=((r*t)/(p+(a/(v**2))))+b]. So the c would become v and compute a new number.

Any ideas on how I could accomplish that? Thanks for help in advance.

 program homework
      open (2, file='output.txt')
      a=366*10**3
      b=0.0429
      p=100
      t=300
      r=8.3145



      DO 1, i=0,5

      v=(r*t)/p
      c=((r*t)/(p+(a/(v**2))))+b



      write(2,*) c
      
      
      
      
   1  continue
      
      
      
      
      end program

 

[.Scott]

First: move the statement "v=(r*t)/p" out of the loop (just before the "do" statement.
Then, after the write statement, add this statement: v=c

That's all it takes.

 

[selmayda]

Hi everyone;
I want to know whether a call statement is used in a do loop. For example;

do 100 ii = 1, 10

call subroutine getsum(ii,20,XX,JJ)

100 continue

Here XX and JJ are parameters.

 

[Mark44]

selmayda,
Please start a new thread with your question. Tacking an unrelated question onto an existing thread is known as "hijacking."

 

[LudusRex]

homework

I would like to commend you for taking the initiative to learn FORTRAN and for seeking help when encountering a problem. It shows your dedication to understanding and solving problems using programming.

To use FORTRAN do loops for solving equations, follow these steps:

1. Define your known values: In your code, you have already defined the values for a, b, p, t, and r. This is a good start.

2. Set up the equation to be solved: In your case, you are solving for v using the equation v=(r*t)/p. This is also already in your code.

3. Use a do loop to iterate through different values of v: In your code, you have used a do loop to iterate through the values of i from 0 to 5. This is a good start, but you need to modify it to iterate through different values of v instead.

4. Within the do loop, calculate c using the equation: c=((r*t)/(p+(a/(v**2))))+b. This will give you a different value of c for each iteration of the do loop.

5. Use the value of c as the new v and repeat the do loop: To do this, you can assign the value of c to v before the next iteration of the do loop. This will use the new value of v to calculate a new value of c, and the process will continue until the do loop reaches the end.

6. Output the values: In your code, you have used the write statement to output the value of c to a file. This is a good way to keep track of the values and compare them.

Overall, your approach seems correct. However, you need to modify your do loop to iterate through different values of v and assign the value of c to v before the next iteration. I hope this helps and good luck with your FORTRAN journey!