TOPS-20 PASCAL Language Manual - Bitsavers

PROCEDURES AND FUNCTIONS
The function COUPONS computes the total value of a group of coupons.
It uses only the three local variables, ANS, AMOUNT, and SUBT, and
requires no parameters. The result of this function is the real totaJ
of the coupon values. The assignment statement, COUPONS := SUBT,
assigns the result to the function identifier.
To use the function COUPONS, specify its name, as follows:
TOTAL := SUBTOTAL -
COUPONS;
The function call is treated as a real-vaJued expression in this
statement. Note that you can use the function call in the same way
that you can use a value of its result type.
Example 2
FUNCTION SYMMETRY