In this tutorial you will learn about the Dart Default Parameter Values and its application with practical example.
Dart Default Parameter Values
In Dart, we can assign default parameter values in a function definition, so when we call that function with no argument passed for a parameter then its default value assigned. When a function is called with argument, then these arguments is used as parameter values in function, but when a function is called or invoked without passing argument for any specific parameters than default parameter values been used as parameters value as per function definition.
Syntax:-
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function_name(param1,param2= default_value) { // Statement(s) } |
Optional Parameters with Default Values
Syntax:-
For Optional Positional Parameters
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function_name(param1,[param2= default_value]) { // Statement(s) } |
Syntax:-
For Optional Named Parameters
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function_name(param1,{param2= default_value}) { // Statement(s) } |
Example:-
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void main() { print("W3Adda - Dart Default Parameter Value."); test_param(12); test_param(123,np1:10); test_param(123,np2:20); test_param(123,np1:10,np2:20); } test_param(p1,{np1=25, np2}) { print("Param Value Is : ${p1}"); print("Named Param 1 Valus Is : ${np1}"); print("Named Param 1 Valus Is : ${np2}"); } |
Output:-
