Explanation::-
A copy by value, means that a value is passed and a copy of the variable is created, so if you change the value, the original var will remain with the same value, the change will affect only the copy.
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It happens usually with primitivy types such as number, string, bool...
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A copy by reference means that a value is passed by reference, and all changes will affect the original object, because it has the reference or memory address pointing to the variable's location in memory.
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It happens usually with non-primitivy types such as objects and arrays.
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