When you define a function, you specify the name and the sequence of statements. We have already seen one example of a function call:
The type of price is "double" i. The function's return type is also a double. When this happens, Therefore, the final result ignoring possible round-off errors one encounters with representing decimal fractions in IEEE format is 0.
Parameters and arguments[ edit ] The terms parameter and argument may have different meanings in different programming languages. Sometimes they are used interchangeably, and the context is used to distinguish the meaning.
The term parameter sometimes called formal parameter is often used to refer to the variable as found in the function definition, while argument sometimes called actual parameter refers to the actual input supplied at function call.
For example, if one defines a function as def f x: A parameter is an unbound variable, while the argument can be a value or variable or more complex expression involving values and variables. Parameters appear in procedure definitions; arguments appear in procedure calls.
Loosely, a parameter is a type, and an argument is an instance. A parameter is an intrinsic property of the procedure, included in its definition. For example, in many languages, a procedure to add two supplied integers together and calculate the sum would need two parameters, one for each integer.
In general, a procedure may be defined with any number of parameters, or no parameters at all.
If a procedure has parameters, the part of its definition that specifies the parameters is called its parameter list.
By contrast, the arguments are the expressions  supplied to the procedure when it is called, usually one expression matching one of the parameters. Unlike the parameters, which form an unchanging part of the procedure's definition, the arguments may vary from call to call.
Each time a procedure is called, the part of the procedure call that specifies the arguments is called the argument list. Although parameters are also commonly referred to as arguments, arguments are sometimes thought of as the actual values or references assigned to the parameter variables when the subroutine is called at run-time.
When discussing code that is calling into a subroutine, any values or references passed into the subroutine are the arguments, and the place in the code where these values or references are given is the parameter list.
When discussing the code inside the subroutine definition, the variables in the subroutine's parameter list are the parameters, while the values of the parameters at runtime are the arguments. At run time the value we use is an argument. It adds the values passed into the parameters, and returns the result to the subroutine's caller using a technique automatically supplied by the C compiler.
The code which calls the sum function might look like this: At runtime, the values assigned to these variables are passed to the function sum as arguments.
In the sum function, the parameters addend1 and addend2 are evaluated, yielding the arguments 40 and 2, respectively. The values of the arguments are added, and the result is returned to the caller, where it is assigned to the variable sumValue.Variable numbers of arguments It is often desirable to implement a function where the number of arguments is not known, or is not constant, when the function is written.
Such a function is printf, described in Section Flow of execution. In order to ensure that a function is defined before its first use, you have to know the order in which statements are executed, which is called the flow of execution..
Execution always begins at the first statement of the program. (varfun() gets the number of arguments from the "add esp,xxx" and there are two forms of the add, (1) short form and (2) long form.
In the 2nd test I passed a struct because I wanted to simulate lots of arguments to force the long form). Yes you can do it in C using what are referred to as Variadic Functions.
The standard printf() and scanf() functions do this, for example.. Put the ellipsis (three dots) as the last parameter where you want the 'variable number of parameters to be. These are called Variadic initiativeblog.comdia lists example code for C++..
To portably implement variadic functions in the C programming language, the standard stdarg.h header file should be used. The older varargs.h header has been deprecated in favor of stdarg.h. This is the c programming questions and answers section on "Variable Number of Arguments Yes / No Questions" with explanation for various interview, competitive examination and entrance test.
Solved examples with detailed answer description, explanation are given and it would be easy to understand.