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Copyright © 2017–2020 EVL Tool, s.r.o.

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Decimal

Decimal data type is defined by ‘decimal(m,n)’, where ‘m’ is number of all digits and ‘n’ is the number of decimal places. Decimal is EVL custom data type.

decimal(m,n)

when ‘n’ is missing, zero is supposed
size: 8 Bytes for ‘m’ up to 18 digits
size: 16 Bytes for ‘m’ from 19 to 38 digits

Next to standard EVD options (i.e. ‘sep=’, ‘null=’, ‘quote=’, ‘optional_quote=’) decimal and thousands separator can be specified:

decimal_sep="."

to specify a decimal separator, which can be any single ascii character below 128; by default it is a decimal point

thousands_sep=""

defines how to separate thousands, it can be any single ascii character below 128; by default there is no thousands separator.

An EVD file example:

revenues  decimal(9,4)  decimal_sep="," thousands_sep="."  // e.g. 12.345,6789
expenses  decimal(18)                        // e.g. 123456789012345678
taxes     decimal(18,6) thousands_sep=" "    // e.g. 123 456 789 012.345678
latitude  decimal(10,6)                      // e.g. 49.8197203
longitude decimal(10,6) decimal_sep=","      // e.g. 18,1673552

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

Important: By any operation, when the precision is decreased, there is no rounding, just cut off!

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