The following code examples and descriptions are taken from an on-line F77 to F90 tutorial by Bo Einarsson of the Mathematics Department of Linköping University, Sweden.
The following simple programs, which use many different and usual concepts in programming, are based on "The early development of Programming Languages" by Donald E. Knuth and Luis Trabb Pardo, published in "A History of Computing in the Twentieth Century" edited by N. Metropolis, J. Howlett and Gian-Carlo Cota, Academic Press, New York, 1980, pp. 197-273.
The name FORTRAN 0 has been given to one of the development phases between 1954
and 1957.
Please note the elegant treatment of the input of the vector A and that the symbol
> (greater than) was available at the beginning of the Fortran development.
Output of text was not available, therefore 999 was used here to mark too big numbers.
The DO-loop was less elegant, the digits give starting line and the final line for the
loop and where the execution should be transferred when the loop is terminated.
The conditional statement is also not very user-friendly. Exponentiation is being
done with **.