# Class Decimal<> (3.7.0-rc)

3.7.0-rc 3.6.0 (latest) 3.5.0 3.4.0 3.3.0 3.2.0 2.48.0-rc 2.47.1 2.46.0 2.45.0 2.44.0 2.43.0 2.42.0 2.41.0 2.40.0 2.39.0 2.38.0 2.37.0 2.36.0 2.35.0 2.34.0 2.33.0 2.32.0 2.31.0 2.30.0 2.29.0 2.28.0 2.27.0 2.26.0 2.25.1 2.24.0 2.23.0 2.22.1 2.21.0 2.20.0 2.19.0 2.18.0 2.17.0 2.16.0 2.15.1 2.14.0 2.13.0 2.12.0 2.11.0 A representation of the Spanner NUMERIC type: an exact decimal value with a maximum integer precision (kIntPrecision) and rounding to a maximum fractional precision (kFracPrecision).
A [`Decimal`](https://docs.cloud.google.com/cpp/docs/reference/spanner/latest/classgoogle_1_1cloud_1_1spanner_1_1Decimal) can be constructed from, and converted to a `std::string`, a `double`, or any integral type. See the `MakeDecimal()` factory functions, the [`ToString()`](https://docs.cloud.google.com/cpp/docs/reference/spanner/latest/classgoogle_1_1cloud_1_1spanner_1_1Decimal#classgoogle_1_1cloud_1_1spanner_1_1Decimal_1ab71ce8fce1c807d7347a04eee60e6d85) member function, and the [`ToDouble()`](https://docs.cloud.google.com/cpp/docs/reference/spanner/latest/namespacegoogle_1_1cloud_1_1spanner)/[`ToInteger()`](https://docs.cloud.google.com/cpp/docs/reference/spanner/latest/namespacegoogle_1_1cloud_1_1spanner) free functions.

[`Decimal`](https://docs.cloud.google.com/cpp/docs/reference/spanner/latest/classgoogle_1_1cloud_1_1spanner_1_1Decimal) values can be copied/assigned/moved, compared for equality, and streamed.

###### Example

    auto d = spanner::MakeDecimal<spanner::DecimalMode::kGoogleSQL>(42).value();
    assert(d.ToString() == "42");
    assert(spanner::ToInteger<int>(d).value() == 42);

## Constructors

### Decimal(Decimal \&\&)

Regular value type, supporting copy, assign, move.

| **Parameter** ||
|---|---|
| **Name** | **Description** |
|   | `Decimal &&` |

### Decimal(Decimal const \&)

Regular value type, supporting copy, assign, move.

| **Parameter** ||
|---|---|
| **Name** | **Description** |
|   | `Decimal const &` |

### Decimal()

A zero value.

## Operators

### operator=(Decimal \&\&)

Regular value type, supporting copy, assign, move.

| **Parameter** ||
|---|---|
| **Name** | **Description** |
|   | `Decimal &&` |

| **Returns** ||
|---|---|
| **Type** | **Description** |
| `Decimal &` |   |

### operator=(Decimal const \&)

Regular value type, supporting copy, assign, move.

| **Parameter** ||
|---|---|
| **Name** | **Description** |
|   | `Decimal const &` |

| **Returns** ||
|---|---|
| **Type** | **Description** |
| `Decimal &` |   |

## Functions

### ToString() const \&

Conversion to a decimal-string representation of the [`Decimal`](https://docs.cloud.google.com/cpp/docs/reference/spanner/latest/classgoogle_1_1cloud_1_1spanner_1_1Decimal) in one of the following forms:
- 0 // value == 0
- -?0.\[0-9\]\*\[1-9\] // 0 \< abs(value) \< 1
- -?\[1-9\]\[0-9\]*(.\[0-9\]*\[1-9\])? // abs(value) \>= 1
- NaN // "not a number" for kPostgreSQL mode

Note: The string never includes an exponent field.

| **Returns** ||
|---|---|
| **Type** | **Description** |
| `std::string const &` |   |

### ToString() \&\&

Conversion to a decimal-string representation of the [`Decimal`](https://docs.cloud.google.com/cpp/docs/reference/spanner/latest/classgoogle_1_1cloud_1_1spanner_1_1Decimal) in one of the following forms:
- 0 // value == 0
- -?0.\[0-9\]\*\[1-9\] // 0 \< abs(value) \< 1
- -?\[1-9\]\[0-9\]*(.\[0-9\]*\[1-9\])? // abs(value) \>= 1
- NaN // "not a number" for kPostgreSQL mode

Note: The string never includes an exponent field.

| **Returns** ||
|---|---|
| **Type** | **Description** |
| `std::string &&` |   |