Normally the execution of the program in c++ starts from main only.

In a function, return type and function name are mandatory all else are just used as a choice.

;

In the call by reference, it will just copy the address of the variable to access it, so it will reduce the memory in accessing it.

127

We have to use the semicolon to declare the function in line 3. If we did means, the program will execute.

In this program, we called by value so the value will not be changed, So the output is 10

The main function is the mandatory part, it is needed for the execution of the program to start.

The variable is valid only in the function block as in other.

There are three ways of passing a parameter. They are pass by value,pass by reference and pass by pointer.