所以我以 .f90 格式编写了一些 Fortran，出于编译原因，我需要将文件扩展名设为 .f。我假设我以最新的 fortran 90 方式编写了 fortran，我需要将其转换回 .f fortran 77 方式。
program p1
implicit none
integer :: choice
real :: inputValue
do while(choice /= 0)
print *, ' '
print *, 'Enter a conversion option (1-6 or 0 to exit):'
print *, '-------------'
print *, '(1) Pounds to Kilograms'
print *, '(2) Kilograms to Pounds'
print *, '(3) Feet to meters'
print *, '(4) Meters to feet'
print *, '(5) farenheit to Celsius'
print *, '(6) Celsius to Fahrenheit'
print *, '(0) Exit this progrm'
print *, '-------------'
READ(*,*) choice
IF (choice == 1) THEN
print *, 'Please enter the number (Integer) of Pounds to be converted into Kilograms'
READ(*,*) inputValue
inputValue = inputValue / 2.20
print *, 'Your value is:', inputValue
ELSE IF (choice == 2) THEN
print *, 'Please enter the number (Integer) of Kilograms to be converted into Pounds'
READ(*,*) inputValue
inputValue = inputValue * 2.20
print *, 'Your value is:', inputValue
ELSE IF (choice == 3) THEN
print *, 'Please enter the number (Integer) of Feet to be converted into Meters'
READ(*,*) inputValue
inputValue = inputValue / 3.28
print *, 'Your value is:', inputValue
ELSE IF (choice == 4) THEN
print *, 'Please enter the number (Integer) of Meters to be converted into Feet'
READ(*,*) inputValue
inputValue = inputValue * 3.28
print *, 'Your value is:', inputValue
ELSE IF (choice == 5) THEN
print *, 'Please enter the number (Integer) of Fahrenheit to be converted into Celsius'
READ(*,*) inputValue
inputValue = (5.0/9.0) * (inputValue - 32)
print *, 'Your value is:', inputValue
ELSE IF (choice == 6) THEN
print *, 'Please enter the number (Integer) of Celsius to be converted into Fahrenheit'
READ(*,*) inputValue
inputValue = (inputValue * 9.0/5.0) + 32
print *, 'Your value is:', inputValue
ELSE IF (choice == 0) THEN
print *, 'EXIT'
END IF
ENDDO
end program p1