1, Different Subjects: When a parameterized function is called by an argument, the parameter in parentheses after the function name is "argument". Formal parameters are not real variables, also called imaginary variables.

2. Different purposes: parameters can be constants, variables or expressions. No matter what kind of quantity, there must be definite values when making function calls, so that these values can be passed to formal parameters.

It should be noted that when the parameters are not pointer types, they are different variables and located in different locations in the memory when the function runs. The formal parameters copy the contents of the arguments, which are released at the end of the function, but the contents of the arguments will not change.