C++auto
The auto Keyword
Theauto keyword automatically detects the type of a variable based on the value you assign to it.
It helps you write cleaner code and avoid repeating types, especially for long or complex types.
For example: Instead of writingint x = 5;, you can write:
Starting inC++11,auto became a powerful way to let the compilerfigure out the type based on the value you assign.
Example with Different Types
Here's an example showing howauto can be used to create variables of different types, based on the values you assign:
Example
auto myNum = 5; // int
auto myFloatNum = 5.99f; // float
auto myDoubleNum = 9.98; // double
auto myLetter = 'D'; // char
auto myBoolean = true; // bool
auto myString = string("Hello"); // std::string
Important Notes
autoonly works when you assign a value at the same time (You can't declareauto x;without assigning a value)- Once the type is chosen, it stays the same. See example below:
x = 10; // OK - still an int
x = 9.99; // Error - can't assign a double to an int
Note: In this tutorial, we usually useint,double, and other basic types when the type is simple and easy to see.
But for more complex types - likeiterators andlambdas, which you will learn more about in a later chapter, we useauto to keep the code cleaner and easier to understand.
