- #1
Nicolaus
- 73
- 0
Can someone give him a head start re: the following Q:
We can make the program test itself by having it plug in the found root and evaluate the LHS (it should be zero). Complete the program by having it evaluate the LHS at x = root1.
! This program finds the roots of equations of the 2nd degree
! with coefficients a, b and c
program Equation
implicit none
real*4 a, b, c, delta
real*4 root1, root2
integer*1 count
! ----------------------------------------------Prompt and Input
print*, "Solves ax^2 + bx + c = 0"
print*, "Enter the coefficients a,b,c separated by commas..."
read*, a, b, c
! ----------------------------------------------Validate
! ----------------------------------------------Find delta
delta = b**2 - 4.* a * c
! ----------------------------------------------Determine Roots
if (delta .GT. 0.) then
root1 = (-b + sqrt(delta)) / (2. * a)
root2 = (-b - sqrt(delta)) / (2. * a)
count = 2
else if (delta .LT. 0.) then
count = 0
else
root1 = -b / (2. * a)
count = 1
end if
! ----------------------------------------------Show Results
if (count .EQ. 2) then
write(*,20) " Equation has two roots: ", root1, ", ", root2
else if (count .EQ. 1) then
write(*,20) " Equation has one root: ", root1
else
write(*,20) " Equation has no real roots!"
end if
20 format(1x, A, F10.4, A, F10.4)
! ----------------------------------------------Verify root1
if (count .GT. 0) then
print*, "Verifying the first root by computing the L.H.S.:"
end if
! ----------------------------------------------
end
We can make the program test itself by having it plug in the found root and evaluate the LHS (it should be zero). Complete the program by having it evaluate the LHS at x = root1.
! This program finds the roots of equations of the 2nd degree
! with coefficients a, b and c
program Equation
implicit none
real*4 a, b, c, delta
real*4 root1, root2
integer*1 count
! ----------------------------------------------Prompt and Input
print*, "Solves ax^2 + bx + c = 0"
print*, "Enter the coefficients a,b,c separated by commas..."
read*, a, b, c
! ----------------------------------------------Validate
! ----------------------------------------------Find delta
delta = b**2 - 4.* a * c
! ----------------------------------------------Determine Roots
if (delta .GT. 0.) then
root1 = (-b + sqrt(delta)) / (2. * a)
root2 = (-b - sqrt(delta)) / (2. * a)
count = 2
else if (delta .LT. 0.) then
count = 0
else
root1 = -b / (2. * a)
count = 1
end if
! ----------------------------------------------Show Results
if (count .EQ. 2) then
write(*,20) " Equation has two roots: ", root1, ", ", root2
else if (count .EQ. 1) then
write(*,20) " Equation has one root: ", root1
else
write(*,20) " Equation has no real roots!"
end if
20 format(1x, A, F10.4, A, F10.4)
! ----------------------------------------------Verify root1
if (count .GT. 0) then
print*, "Verifying the first root by computing the L.H.S.:"
end if
! ----------------------------------------------
end