program to convert object to string

void main(){
Object name = "Pratik";
// print(name.length) will not work because Dart doesn't know that name is a String

if(name is String) {
// name promoted from Object to String
  print("The length of name is ${name.length}");
}
}

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example of type promotion

void main(){
// result is a String
String result;
// result is promoted to a non-nullable type String
if(DateTime.now().hour < 12) {
  result = "Good Morning";
} else {
  result = "Good Afternoon";
}
// display the result
print("Result is $result");
print("Length of result is ${result.length}");
}

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example of type promotion with nullable to non-nullable type

// method to print the length of the text
void printLength(String? text){
    if(text == null) {
        throw Exception("The text is null");
    }
    print("Length of text is ${text.length}");
}
// main method
void main() {
    printLength("Hello");
}

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