Can you explain what the equality comparison operator with double equals means in programming languages?

The comparison operator with double equals (==) is used to check the equality of two expressions' values.

In most programming languages, it checks whether the values are equal in meaning, not necessarily by reference or memory address. For example, in Dart (used in Flutter), == compares the contents of objects if the class overrides this operator.

Example in Dart:

int a = 5;
int b = 5;
print(a == b); // true

String s1 = 'hello';
String s2 = 'hello';
print(s1 == s2); // true

It is important not to confuse it with the assignment operator =, which assigns a value to a variable.