Identify the errors in the function skeletors given below :

float average (a, b) { }

Identify the errors in the function skeletors given below :

float mult (int x, y) { }

Given the method below, write a main() method that includes everything necessary to call given method.

int thrice (int x)
{
return x * 3 ;
}

What is the principal reason for passing arguments by value ?