Control
Structure
A statement used to control
the flow of execution in a program is called control structure. The
instructions in a program can be organized in three kinds of control structures
to control execution flow. The control structure is used to implement the
program logic.
Types of
Control Structure
Different types of
control structure are as follows:
Sequence
In sequential structure, the statements are executed in the same order
in which they are specified in program. The control flows from one statement to
other statement in logical sequence. All statement is executed exactly once. It
means that no statement is skipped and no statement is executed more that once
Example
Suppose a program inputs two
numbers and displays average on screen. The program uses two statements to
input numbers, one statement to calculate average and one statement to display
average number. These statements are executed in a sequence to find the average
number. All statements are executed once when the program is executed. It is an
example of sequence control structure.
Selection
A
selection structure selects a statement or set of statements to execute on the
basis of a condition. In this structure, statement or set of statement is
executed when a particular condition is true and ignored when the condition is
false. There are different types of selection structure in C++ these are if….else and switch.
Example
Suppose a program inputs the
marks of a student and displays a message on screen whether the student is pass
or fail. It displays pass if the
student gets 40 or more then 40 marks. It displays fail when the marks are below 40. The program checks the marks
before displaying the message. It is an example of selection structure.
Repetition
A
repetition structure executes a statement or set of statements repeatedly. It is
also known as iteration structure or loop. There are different types of
repetition structure in C++. These are while,
do while and for.
Example
Suppose we want to display a
Name “Umair Jatoi” on screen for 100 times. It is time consumi9ng to perform
this task using control sequence; however, it is very easy to perform this task
using repetition structure. A single loop statement can display the message for
100 times.
Function
call
Function
call is a type of statement that moves the control to another block of a code
the control returns back after executing all statement in the block. The
remaining statement are executed immediately after the function call when the
control returned
