Functions with Optional Parameter
There are also optional parameter system in Dart which allows user to give some optional parameters inside the function.
| Sr. No. | Parameter | Description |
|---|---|---|
| 1. | Optional Positional Parameter | To specify it use square (‘[ ]’) brackets |
| 2. | Optional Named parameter | When we pass this parameter it is mandatory to pass it while passing values. It is specify by curly(‘{ }’) brackets. |
| 3. | Optional parameter with default values | Here parameters are assign with default values. |
Example:
void gfg1(int g1, [ var g2 ])
{
// Creating function 1
print("g1 is $g1");
print("g2 is $g2");
}
void gfg2(int g1, { var g2, var g3 })
{
// Creating function 1
print("g1 is $g1");
print("g2 is $g2");
print("g3 is $g3");
}
void gfg3(int g1, { int g2 : 12 })
{
// Creating function 1
print("g1 is $g1");
print("g2 is $g2");
}
void main()
{
// Calling the function with optional parameter
print("Calling the function with optional parameter:");
gfg1(01);
// Calling the function with Optional Named parameter
print("Calling the function with Optional Named parameter:");
gfg2(01, g3 : 12);
// Calling function with default valued parameter
print("Calling function with default valued parameter");
gfg3(01);
}
Output:
Calling the function with optional parameter:
g1 is 1
g2 is null
Calling the function with Optional Named parameter:
g1 is 1
g2 is null
g3 is 12
Calling function with default valued parameter
g1 is 1
g2 is 12
Dart – Functions
The function is a set of statements that take inputs, do some specific computation and produces output. Functions are created when certain statements are repeatedly occurring in the program and a function is created to replace them. Functions make it easy to divide the complex program into smaller sub-groups and increase the code reusability of the program.
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