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to compute the interest of another person (a) User-defined function
who also deposited money in the bank. A user-defined function is the type of
Alternatively, we would rather move to function designed by a programmer
a ‘code section’ that calculates interest according to the user’s requirement.
and then return to where you left off. Programmers use the function to break Chapter Four: Object oriented programming with C++
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down large programs to simplify
Advantages of functions debugging, testing, and maintenance of
(a) Using functions facilitates the reuse the program. A user-defined function
of the codes in writing computer that returns value is called ‘returning
programs function’. The function that does not

(b) The use of functions help to improve return value is called ‘void function’.
the program’s readability because it
reduces the complexity of the main Elements of user-defined function
function User-defined function contains three

(c) Functions help you to focus on just elements: function definition, function
that part of the program and construct call and function prototype.
it, debug it, and perfect it.
(d) Different people can work on (i) Function definition
different functions concurrently. Function definition specifies all

The following is the syntax of typing a characteristics and elements required
function: in a user-defined function. Function
returnValueType functionName (list definition includes function header and
of parameters) function body. Function header includes
{ data type or returns type, function name,
//Function body; and a list of parameters. On the contrary,
}
Types of functions function body involves all executable
statements within it. Figure 4.55 shows
There are two types of functions applied the components of function definition.
in C++ programming, namely user-
defined function and built-in/pre-defined int sum (int x, int y)
function as shown in Figure 4.54. Function header

Functions
sum = x + y;
cout<< “The total is”<<sum>>endl;

Built-in User-defined
Functions Functions Function body

Figure 4.54: Types of functions Figure 4.55: Components of function definition

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Student’s Book Form Five

Computer Science Form 5.indd 275 23/07/2024 12:34