Intel fortran-80 manual Chapter Introduction To Fortran, An Introductory Example, Comment Lines

CHAPTER 11

INTRODUCTION TO FORTRAN

This chapter opens with a short example intended to give the newcomer to FOR- TRAN a feel for the language. The example is discussed in some d.etail. The chapter also includes a summary of FORTRAN-80 statements and their proper coding se- quence.

1.1 An Introductory Example

A FORTRAN program generally performs three basic operations: receiving input, processing the data received, and returning output. The following short program, drawn from the statistical world of the sports fan(atic), shows typical FORTRAN statements for doing these operations.

The example calculates a baseball player's batting average using the equation:

AVERAGE =

HITS

TIMES AT BAT

The baseball statistician, sitting at his console terminal, enters the name of a player, how often he has batted, and his total hits. The program returns a listing showing the player's name and batting average. To keep this example simple, the calculation is done only once.

1.1.1 Comment Lines

The first seven lines of the example are comment lines. Comment lines are used to

document a program. .

A comment line must have the letter 'C' or an asterisk (*) in column 1 followed by any characters accepted by FORTRAN in the remainder of the line. A completely blank line is considered a comment line also. For example, the 'C' need not be pre- sent in line 7 of the example. Comment lines have no effect on program execution.

CCALCULATE BATTING AVERAGES C VARIABLES USED-

C PNAME = PLAYER'SNAME C AB = TIMES AT BAT CHITS = TOTAL BASE HITS C AVG = BATTING AVERAGE

C

CHARACTER*12 PNAME READ 10, PNAME, AB, HITS

10 FORMAT (A, 2(2X, F3.0))

AVG = HITS/AB

PRINT 20, PNAME, AVG

20 FORMAT (A, 5X, F4.3)

END

Fig. 1-1 Batting Average Program

1-1