Glossary
a.out - Executable program that can be run on a computer.
.and. - used to join two tests in an 'if statement' in which both must be true to proceed into the 'if statement'
array - a variable that can hold numerous numbers. A variable array declared as 'real t(3)' can hold three values call t(1), t(2), and t(3).
assignment statement or operator - The '=' sign in Fortran is used in calculations. The right hand side is calculated and then assigned to the left hand side variable by the assignment operator.
close - used to relinquish the connection between a file and the running program. it allows the unit number to be used again for connecting to other files.
code or source code - this the Fortran programming language that you write into a file prior to compilation.
compile - after you have written your program source code and you are ready for the computer to run the program then you need to compile it to produce the a.out executable.
criteria - this is a statement that makes up the test for 'if statements'.
declaration or declare - declarations are when you tell the computer what type of numbers will be stored for a variable. For example, if 'a' is declared as real then it can take on real numbers. If 'i' is declared as an integer then it can take on whole numbers, both positive and negative values and zero.
else/elseif - used to create other options with 'if statements'. The elseif will include a further test whereas if the else is reached then it is always performed.
endif - used to denote the end of an 'if statement'.
executable - this is the same as the a.out, it is the executable program that can be run on the computer.
executable statements - this is a term used to point out that lines of code would be present where it is labelled 'executable statements'.
f77 - compilation program that converts source code (e.g. program.f) into an executable (e.g. a.out).f77 is used to compile fortran 77 source code.
f95 - compilation program that converts source code (e.g. program.f) into an executable (e.g. a.out). f95 is used to compile fortran 95 source code but will also compile fortran 77 code.
functions - are either intrinsic or user defined. The intrinsic functions are made available by the fortran compiler for standard functions like sin(x), log(x), etc. User defined functions are written by the user to calculate a single value.
if or 'if statements' - begins an 'if statement' and hence a decision by the program. The 'if statement' is everything between 'if' and 'endif'.'
index - usually an integer used to keep track of how many times the program has looped around or which variable in an array is being used.
integer - a number that is a whole number and includes zero and both positive and negative numbers.
input/output or I/O - when a program runs, numbers (or characters) brought into the running program are input and numbers used in the program that are printed to the screen or stored in a file by the program are called output.
loop - the start is defined by the word 'do' and the end by the word 'enddo' or 'end do'. The program cycles around between these start and end points a set number of times defined by an index.
modules - these are like libraries of source code that can be made easily available to any program.
nested - means more than one (e.g. 'if statement' or do loop) if statement or do loop within another.
open - a command used to link input and output files to a program.
.or. - used to join two tests in an 'if statement' in which one must be true to proceed into the 'if statement'.
print - output from the program that is printed to the screen.
read - command used to gather values input from the keyboard or from a file.
real - a real number is any rational or irrational number.
source code - this is the Fortran programming language that you write into a file prior to compilation.
stop - terminates a program as soon as the stop is reached.
subroutines - these are used to separate the code into smaller bite-size bits of code that perform certain tasks.
test - used in 'if statements' to determine if the program should enter an if statement.
unit number - a unique number to 'label' or 'represent' the file being attached to the program. It is a nickname for the file.
write - used to output data to the screen or to a file.