It is usually necessary to prompt the user for data. This is done by means of the writeln or write statement. The difference between writeln and write is that writeln moves to the next line after the write operation whereas write does not. As the above program is written, the computer has not been instructed as to the format for printing out the discount factor df. The equal sign by itself stands for testing for equality.
Division requires a little care.
Division of integers requires two special operations, denoted as div and mod . In Pascal there are a variety of loops. The simplest is the FOR loop. Another important instruction is the IF statement. The ELSE clause is optional.