autoauto

Although C++ is a typed language, you can use auto when initializing a variable to determine the type automatically.
This feature was introduced in C++14 and does not work with older versions.
Here is an example:

cpp

main.cpp

Note that it is harder to catch errors when using auto.
Consider the example:

cpp

main.cpp

Specifying types would help us understand code better and find what's wrong:

Any of num1, num2 or num3 should be float to output the correct result.

Nevertheless, auto is widely used in range-based for loops since it is a versatile method of iterating over arrays and other containers. Just use the following syntax for iterating over arr:

cpp

main.cpp

It can be used when the type is long to type but is clear from the context and can't lead to incorrect results.
Here is an example with iterators:

Don't worry if you don't understand the code above. Containers and iterators are not the topics of this course. This example is used to show you that sometimes custom data type names can be pretty long

auto can also be used in function parameters:

Everything was clear?

Section 3. Chapter 4