In programming, when a function receives a copy of an argument's value, allowing the original variable to remain unchanged, what parameter passing mechanism is being used?

The parameter passing mechanism being used when a function receives a copy of an argument's value, allowing the original variable to remain unchanged, is called Pass by Value. In this mechanism, when a function is called, a completely new, independent copy of the argument's data is created and assigned to the function's parameter. An argument is the actual data or variable supplied when the function is invoked, while a parameter is the local variable defined within the function's signature that receives this incoming data. Because the function operates on a separate copy, any modifications made to the parameter inside the function are confined to that copy and do not affect the original variable that was passed as the argument outside the function's scope. For example, if a variable `x` with a value of `10` is passed by value to a function `increment(num)`, and `num` is changed to `11` inside `increment`, the original `x` outside the function will still hold the value `10`. This mechanism ensures that the function's internal operations are isolated and prevents unintended alterations to external data, promoting modularity and reducing side effects.