z/OS V1R9.0 UNIX System Services Command ... - Christian Grothoff

}
# restore the old scale
scale=old_scale
return (x)
3. Here is a function you can define to return the fractional part of a number:
define fractional_part(x) {return (x - integer_part(x))}
4. The following function lets you set the scale of number to a given number of
decimal places:
define set_scale(x, s)
{ auto os
os = scale
scale = s
x /= 1
scale = os
return (x) }
You can now use set_scale() in a function that rounds a number to two decimal
places:
define round2(num) {
auto temp;
if(scale(num) < 2) return (set_scale(num, 2))
temp = (num - set_scale(num, 2)) * 1000
if(temp > 5) num += 0.01
return (set_scale(num,2))
}
This is a very useful function if you want to work with monetary values. For
example, you can now rewrite sales_tax() to use round2():
define sales_tax(purchase,tax) {
auto old_scale
scale = 2
tax = round2(purchase*(tax/100))
scale = old_scale
return (tax)
}
5. Here is a function that recursively calculates the factorial of its argument:
define fact (x) {
if(x < 1) return 1
return (x*fact(x-1))
}
You can also write the factorial function iteratively:
define fact (x) {
auto result
result = 1
while(x>1) result *= x--
return (result)
}
With either version, fact(6) returns 720.
6. Here is another recursive function, that calculates the nth element of the
Fibonacci sequence:
define fib(n) {
if(n < 3) {
return (1)
} else {
return (fib(n-1)+fib(n-2))
}
}
bc
Chapter 2. Shell command descriptions 63