DECR

Decrement a numeric variable

DECR variable

Arguments

variable

The variable to be decremented. (n)

Discussion

The DECR statement decreases the value of a specified numeric value by 1.

The value of variable can be positive or negative. If the decremented value of variable overflows its size, variable is set to its zero representation. For example, the following code fragment decrements dvar from -9 to 0, because dvar is a d1 field instead of a d2:

record
    dvar        ,d1,    -9
proc
    decr dvar

Using the DECR statement is more efficient than subtracting 1 from a variable.

With integer variables, if the variable has the maximum negative value for its size, the following statements have different results:

decr ivar
ivar = ivar - 1

In the example below, i1 = i1 – 1 is equivalent to i1 = -129, which results in 127. See Moving integer data to an integer destination for more information. This behavior is consistent with the behavior of decimal variables, which may be used as counters.

record
    i1   ,i1,   -128                    ;Max negative value for an i1 field
proc
    decr i1                             ;Result is 0
    i1 = -128
    i1 = i1 - 1                         ;Result is 127