Decimal
EVD definition
Decimal data type is defined by ‘decimal(x,y)’, where ‘x’ is number of all digits and ‘y’ is the number of decimal places.
costs decimal(8,2) // 123456.78 vat decimal(4,1) // 123.4
Up to 18 digits the decimal occupies 8 Bytes.
From 19 to 38 digits it occupies 16 Bytes.
By default decimal separator is a decimal point ‘.’ and no thousand separator. Other separators can be specified this way:
costs decimal(8,2) decimal_sep="," // 123456,78 vat decimal(8,2) decimal_sep="," thousands_sep="." // 123.456,78
Declaration in mapping
Object creation:
decimal d(); // 0 no decimal places
decimal d(821); // 821 initialization from int, no dec. places
decimal d(821, 3); // 821.000 initialization from int, 3 dec. places
decimal d(821.658, 3); // 821.658 init. from float/double, 3 dec. places
decimal d2(d, 2); // 821.65 initialization from existing object,
// just change decimal places to 2 (cut off)
Manipulation, comparison
Increment/decrement:
d++; ++d; d--; --d;
All following operations can be done between two decimals or between decimal and any integral data type:
d += 100; // 921.65 d -= decimal(0.66, 3); // 920.990 d *= -2 // -1841.980 d /= 2 // -920.990 decimal d2 = d + 120; // -800.990
When adding, subtracting or dividing, the result has higher decimal places from both operands. When multiplying two decimals, the decimal places are added.
1.23 + 6.0000 = 7.2300 1.23 - 6.0000 = -4.7700 1.23 * 6.0000 = 7.380000 1.23 * 6.0000 = 0.2050
Comparison as usual: ‘==’, ‘!=’, ‘<’, ‘>’, ‘<=’, ‘>=’.
if (d > 128) ... if (d == decimal(123.456, 3)) ... if (d <= d2) ...
The decimal places can be obtained and set by the following tho methods.
d.scale() // 3 d.set_scale(2) // set the scale to 2
These methods convert decimal to other data types
int i = d.to_int(); // cut off fractional part
float f1 = d.to_float();
double f2 = d.to_double();
string str = d.to_string('.', ''); // decimal_separator = '.'
// thousand_separator = ''
string str = d.to_string(); // use default separators
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The reason is performance, to rounding the number, use ‘round()’ method:
decimal costs(856.128, 3); // 856.128 decimal costs_rounded = costs.round(2); // 856.130 decimal costs_cut_off(costs, 2); // 856.12