10.8: Advance Clause

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The advance clause instructs the computer whether or not to advance the cursor to the next line. The possible values are “yes” and “no”. If the advance clause is not included, the default value is “yes”. This clause is useful when prompting for user input to allow the input to be entered on the same line as the prompt. When using the advance clause, the free format (*) is not allowed. A format must be included.

For example, the period program from the previous chapter included the statements:

! prompt for and read the n value
    write (*,'(a)') "Enter count to sum: "
    read (*,*) n

Which, when executed, the input is entered on the line following the prompt.

c:\mydir> sums
 Example Program
    Difference between sum of squares
    and square of sums

 Enter count to sum:
10
 Difference:         2640

When the advance clause is used with the setting of “no”, as follows:

! prompt for and read the n value
    write (*,'(a)', advance="no") "Enter count to sum: "
    read (*,*) n

The resulting execution would be as follows:

c:\mydir> sums
 Example Program
    Difference between sum of squares
    and square of sums

 Enter count to sum: 10
 Difference:         2640

Which allows the input to be entered on the same line as the prompt.