Decimal Arithmetic

It is very important to bear in mind the rules that apply to decimal arithmetic when dealing with variables with different decimal precisions. The are the following:

If you want a variable to handle a determined precision, you must declare it: Decimal(precision).
In an addition or a subtraction, the result takes the highest precision of the two operands.
In a multiplication, the precision of the result is the sum of the precisions of the two operands.
In a division, the result has the precision of the left operand (the dividend).
In an assignment:
- it takes the precision resulting from the operation if the left operand has no precision defined or if its precision is higher.
- it takes the left operand precision when it is lower than the precision resulting from the operation.
Every time the precision is reduced, the resulting value is rounded. For example, 0.5 is rounded to 1 and not to 0.

Assignment

dec4 = 10.20 
dec2 = dec4 
dec1 = dec4 
dec3 = dec4 

display 'dec1: ' + dec1 + ', dec2: ' + dec2 + ', dec3: ' + dec3 + ', dec4: ' + dec4

This example displays the following:

dec1:10.2000, dec2: 10.20, dec3: 10, dec4: 10.2

Addition

dec1 = 10.20
dec2 = 1.04 
dec3 = 100.003 

res1 = dec1 + dec2 
res2 = dec1 - dec2 
res3 = dec1 + dec2 + dec3 
res4 = dec3 - dec2 

display 'res1: ' +res1 + ', res2: ' + res2 + 
 ' , res3: ' + res3 + ', res4: ' + res4

This example outputs the following:

res1:11.2400, res2:9.1600, res3: 111.2400, res4:98.96

Multiplication

dec1 = 10.20 
dec2 = 1.04 
dec3 = 100.003 
res1 = dec1 * dec2 
res2 = dec2 * dec1 
res3 = dec3 * dec1 
res4 = dec1 * dec1 
display 'res1: ' +res1 + ', res2: ' + res2 +
 ', res3: ' + res3 + ', res4: ' +
res4

This example outputs the following:

res1: 10.608000, res2:10.608000, res3: 1020.0000, res4: 104.04000000

Division

dec1 = 10.20 
dec2 = 1.04 
dec3 = 100.003 
res1 = dec1 / dec2 
res2 = dec2 / dec1 
res3 = dec3 / dec1 
res4 = dec1 / dec1 
display 'res1: ' +res1 + ', res2: ' + res2 +
 ', res3: ' + res3 + ', res4: ' +
res4

This example outputs the following:

res1: 9.8077, res2: 0.10, res3: 10, res4: 1.0000