# Optional Positional Parameter
void function_name(param1, [optional_param_1, optional_param_2]) { }
If an optional parameter is not passed a value, it is set to NULL.
Example
void main() {
pos_param(test);
}
pos_param(n1,[s1]) {
print(n1);
print(s1);
}
It should produce the following output−
test null
# Optional Named Parameter
Declaring the function
void function_name(a, {optional_param1, optional_param2}) { }
Calling the function
function_name(optional_param:value,…);
Example
void main() {
test_param(i am human);
test_param(i am human,s1:'hello');
test_param(i am human,s2:'hello',s1:'world');
}
test_param(n1,{s1,s2}) {
print(n1);
print(s1);
}
It should produce the following output−
i am human null i am human hello i am human world
# Optional Parameters with Default Values
function_name(param1,{param2= default_value}) {
//......
}
Example
void main() {
test_param(hello);
}
void test_param(n1,{s1:world}) {
print(n1);
print(s1);
}
=> output
hello world