DART – Function

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Dart is a modern, object-oriented programming language that is used to build scalable and high-performance applications.

One of the key components of Dart is its function. A function is a reusable block of code that can be called by other parts of your program. Functions help you organize your code, reduce repetitive tasks, and make it easier to debug and maintain your code.

In Dart, functions are declared using the void or return keywords. The void keyword is used when a function does not return a value, while the return keyword is used when a function returns a value.

Here is an example of a simple Dart function that takes two parameters and returns the sum of those parameters:

int sum(int a, int b) {
  return a + b;
}

In this example, the function is named sum and it takes two parameters, a and b, which are both integers. The function uses the return keyword to return the sum of a and b.

You can call a Dart function by simply referencing its name and passing in the required parameters. For example, you can call the sum function like this:

int result = sum(5, 10);

In this example, the sum function is called with the parameters 5 and 10, and the result is stored in a variable named result.

Dart functions can also have optional parameters, which are declared using square brackets []. Optional parameters are parameters that are not required to be passed in when a function is called. Here is an example of a Dart function with optional parameters:

int multiply(int a, int b, [int c = 1]) {
  return a * b * c;
}

In this example, the function is named multiply and it takes two required parameters, a and b, and one optional parameter, c. The default value of c is 1, so if c is not passed in when the function is called, the value of c will be 1.

Dart functions can also accept an arbitrary number of parameters by using the ... syntax. This is known as a “rest” parameter. Here is an example of a Dart function with a rest parameter:

int sumAll(int first, int second, [int third, int fourth, ...int rest]) {
  int result = first + second;

  if (third != null) {
    result += third;
  }

  if (fourth != null) {
    result += fourth;
  }

  for (int i in rest) {
    result += i;
  }

  return result;
}

In this example, the function is named sumAll and it takes two required parameters, first and second, and two optional parameters, third and fourth. The rest parameter is a list of integers that can accept any number of values.

In conclusion, Dart functions are a powerful and versatile tool that can be used to make your code more organized and easier to maintain. With their ability to accept parameters, optional parameters, and a rest parameter, Dart functions can handle a wide range of use cases and help you build high-performance applications.