HOMEWORK assigned August 26, 2004

• Download a FORTRAN compiler

• Get yourself an account on Raven

• Look on the web for information about early FORTRAN language

• Read or re-read chapter 1 and chapter 2 up through FORTRAN section

What do you need to know to write/run a program in a new language?

• y How to declare variables – if variables are declared
• y What is the assignment operator – if there is one
• y What does the program header statement look like – if there is one
• y What kinds of conditional branches are there – if any
• y What kinds of loop statements are there – if any
• y Basic syntax
• How do you compile it?
• y What arithmetic operators are there?
• How do you write/call functions – if there are any
• What are the naming convention – if there are any
• Are there header files needed? None
• How are variables stored in memory?
• y How do you comment?
• How do you terminate the program
• What paradigm does it use?
• What are the keywords – if any
• How do produce output?
• How do you obtain input?

Some answers to above questions

Basic Syntax

Variable names are all uppercase

Variable names limited to 6 characters (first required to be alphabetic rest

can be alphanumeric)

Variables names which begin w/ A-H and 0-Z are by default floating point or

real variables

Variables which begin with I-N are by default integers

Early FORTRAN had no character variables

Could change default by saying “INTEGER apple”

FORTRAN had to be written in particular columns

-Column 1 were comments

-Column 2-5 held numeric labels

-Column 6 reserved for continuation

-Column 7 – 72for program statements

-Column 72-80 reserved for numbering the cards (purely to

reassemble punch cards in order)

Spaces between variable names ignored i.e R E D is same as RED

What is the assignment operator

=

What does the program header statement look like

None

What kinds of conditional branches are there

Go to 10 - unconditional branch

If statement – discussed in class

IF (X .LE. 5.3) Y = 23

Computed go to

go(10, 12, 16, 18, 197, 6)I

If I has value of 1, goes to first number and so forth

Arithmetic if

If(J) 10, 144, 367

3 way branch- J<0 goes first number, J=0 goes to 2^nd number, J>0

goes to 3^rd number

What kinds of loop statements are there

Essentially only had for loop

Do 10 x = 1, 15, 3

c (coding)

10 continue

sets x to 1, continues while x is less than 15 and is incremented by 3

What arithmetic operators are there?

*, **, +, -

SQRT(), IFIX(), etc

How do you terminate the program

Stop (can be written anywhere and stops program at this point)

End (marks end of code where compiler stops)