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How to convert Double to Integer or Integer to double in Dart| Flutter By Example

This tutorial shows multiple ways to Convert `Double` to `Int` and `Int` to `double` in Dart and Flutter programming.

• Convert Double to Int in Dart:

• First Way, use `double.toInt()` method, For example: `3.4.toInt()` returns `int` value `3`.
• Second way, use `double.truncate()` method to remove decimals from a number.`3.4.truncate()` returns `int` value `3`.
• Third way, use rounding methods such as `round`, `ceil`, and `floor` based on lower or upper value of a given number.
• Convert Int to Double in Dart:

• `Int.toDouble()` returns `double` value
• `double.parse(numberstring)` method that takes number string, returns `double`, Example `double.parse("123")` returns double 123
• use `division`(/) operator to divide number by 1.

let’s see what are `Int` and `Double` types in Dart and Flutter.

`Int` is a primitive type that stores numeric numbers arbitrary-precision signed integer without decimals, Examples 1 types values are 1,5.

`Double` is a primitive type that stores `IEEE-754` double-precision floating numbers. Example double type values are 1.34,1.0.

`Int` and `Double` are different types and hold different values. Automatic conversion does not happen in the Dart compiler.

We have to convert from one type to another type manually

How to convert Double to Int type in Dart?

There are multiple ways we can parse `double` to `int` in dart programming.

• use Double toInt() method

Double contains number with decimals. `double.toInt()` method removes the decimals from a given double number and returns the `int` value.

Syntax.

``````Int toInt()
``````

Returns integer number.

Here is a `Double toInt() Example`

``````main() {
double double1 = 3.4;
print(double1.runtimeType); // double
int i1 = double1.toInt();
print(i1); // 3
print(i1.runtimeType); // int
}
``````
• Double truncate() method

`double.truncate()` method also ignores the decimal value and returns the `int` value.

Syntax:

``````int truncate()
``````

Here is a `double truncate() example program`

``````main() {
double double1 = 12.9;
print(double1.runtimeType); // Double
int i1 = double1.truncate();
print(i1); // 12
print(i1.runtimeType); // int
}
``````

Another way, using methods - `round()`, `ceil()`, `floor()` which does round a given `double` number in dart and flutter.

• rounded a numbers using `round()`,`ceil()`, `floor()`

• `round() method`: returns the closest int number. For example, 6.5.round() returns 7.

Here is a `round() method example program`

``````    main() {
double double1 = 12.9;
double double2 = 3.4;

print(double1.runtimeType); // double
print(double2.runtimeType); // double

int i1 = double1.round();
print(i1); // 13
print(i1.runtimeType); // int
int i2 = double2.round();
print(i2); // 3
print(i2.runtimeType); // int
}
``````
• ceil() method: returns the ceiling number which is upper of a given int part. For example, 9.5.round() returns 10.

Here is a `ceil() method example program`

``````    main() {
double double1 = 12.9;
double double2 = 3.4;

print(double1.runtimeType); // double
print(double2.runtimeType); // double

int i1 = double1.ceil();
print(i1); // 13
print(i1.runtimeType); // int
int i2 = double2.ceil();
print(i2); // 4
print(i2.runtimeType); // int
}
``````
• floor() method : returns the rounded floor number which is lower than a given int part. For example, 9.5.round() returns 9.

Here is a `floor() method example program`

``````main() {
double double1 = 12.9;
double double2 = 3.4;

print(double1.runtimeType); // double
print(double2.runtimeType); // double

int i1 = double1.floor();
print(i1); // 12
print(i1.runtimeType); // int
int i2 = double2.floor();
print(i2); // 3
print(i2.runtimeType); // int
}
``````

All the above methods work in flutter programming to convert `double` to `int`.

How to parse int to double in Dart or Flutter?

For example, an int value directly assigned to a double value gives the error A value of type ‘int’ can’t be assigned to a variable of type ‘double’. for a below code.

``````  int number = 10;
double dd=number;
``````

Following are multiple ways to convert int type to double in flutter or dart.

• use int toDouble method

`toDouble()`method of int can be assigned to double type. Here is an example:

``````main() {
int number = 10;
double d1 = number.toDouble();
print(d1); //10
print(d1.runtimeType); //10
}
``````
• double parse method

First, get the string version of a number, Next, pass this string to `double.parse()`, assigned to a double number. Here is an example:

``````main() {
int number = 10;
double d1 = double.parse(number.toString());
print(d1); //10
}
``````
• use the divide operator with 1

This is simple and easy as all the division operation results in Double flutter.

Divide the integer number by 1 results in a double type value. Here is an example:

``````main() {
int number = 10;
double d1 = number/1;
print(d1); //10
}
``````

Conclusion

To summarize, We can easily convert numeric types with built-in methods provided by int and double.

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