Chapter#1 Chapter#10 Chapter#11 Chapter#12
Chapter#12
LOOP CONSTRUCTORS
There are Two-Types of Loops.
It is a control structure which is used to repeat set of statements up to a fixed number of times.
for loop: -
It is a counter loop.
It repeats set of statements up to a fixed number of times.
User knows in advance that how many times the loop will be executed.
It consists of Two Parts.
It is the first part of the for loop.
It consists of Three Expressions.
• It is the first expression of loop header.
• In this expression, loop control variable is initialized.
• It is terminated by statement terminator.
• It is an optional part.
This part runs only for one time in the first iteration.
Condition:-
• After initialization, control is transferred to the conditional part.
• In this part, given condition is evaluated.
• If the condition is true, body of the loop is executed.
• If the condition is false, body of the loop is ignored and control is transferred to the statement which comes after the body of the loop.
• It is necessary for the condition of the loop to get false, otherwise loop becomes infinite loop.
• It is terminated by statement terminator.
Inc/Dec:-
• It is the third expression of the loop header.
• After executing the body of the loop control is transferred to this expression.
• This part is responsible to make the condition of the loop false.
• After inc/dec, condition is again tested.
Syntax Of for Loop:-
Conditional Loop:-
• It is a control structure which is used to repeat set of statements until given condition is satisfied.
• There are two types of conditional loop
while Loop:-
• It is a conditional loop.
• It repeats set of statement until given condition is satisfied.
• It is possible in while loop, not to execute body of loop even for one time.
• It is also called top tester because it checks the condition at top and then execute the statements.
• If the condition is true, body of the loop will be executed.
• If the condition is false, body of the loop will be ignored.
• Inc/Dec expression is written inside the body of the loop.
Syntax Of while Loop:-
do-While Loop:-
• It is a conditional loop.
• It repeats set of statement until given condition is satisfied.
• It is called bottom tester.
• It executes the body first and then checks the condition at the last.
• In this loop, body is executed at least one time.
• Two keywords are used in it
• while represent the end of the loop.
• while statement contains the condition and it is terminated by statement terminator.
• If the condition is true, control is transferred to the start of the loop.
• If the condition is false, control is transferred to the next statement after the loop.
Syntax Of do-while Loop:-
• A value which ends the loop is called sentinel value.
e.g:- [Y/N]
• It is normally a conditional loop.
Iteration:-
Get a value
Compare it with sentinel value.
If the value is sentinel, it terminates the loop.
If the value is not sentinel, then get the next value again.
Nested Loop:-
• Loop within the body of another loop is called nested loop.
• Nesting can be performs up to any level.
• Nesting increases the complexity of the program.
• Any loop can be placed within the body of another loop.
• For every iteration of the outer loop, inner loop runs completely.
• Outer loop controls the number of rows.
• Inner loop controls the number of columns.
Syntax Of Nested Loop:-
Array:-
• It is the collection of variables, stored in a contagious portion of the memory having same name and same data type.
• Each portion of the memory is called element of the array.
• Each element is accessed by a unique number called subscript or index.
• Index always starts with 0.
• Range of index is = 0length-1.
Continue Statement:-
• This statement is normally used within the body of the loop.
• When this statement is executed, all the remaining statements are ignored and control is transferred to the start of loop for next iteration.
Syntax of continue statement:-
Following syntax is general syntax of continue statement.
• This statement is used for un-conditional transfer of control from one place to another place in the program.
• Normally this statement is not preferred in the program.
Syntax Of goto Statement:-
Following syntax is a general syntax of goto statement.
THE END
________________________________________
Chapter#12
LOOP CONSTRUCTORS
Loop Control Variable:-
A variable which is used to control the number of iteration of the loop is called loop control variable.
Loops:-
It is a control structure which is used to repeat set of statements up to a fixed numbers of times or until given condition is satisfied.There are Two-Types of Loops.
i. Counter Loop
ii. Conditional Loop
Counter Loop:-It is a control structure which is used to repeat set of statements up to a fixed number of times.
for loop: -
It is a counter loop.
It repeats set of statements up to a fixed number of times.
User knows in advance that how many times the loop will be executed.
It consists of Two Parts.
i. Loop Header
ii. Loop Body
Loop Header:-It is the first part of the for loop.
It consists of Three Expressions.
i: Initialization
ii: Condition
iii: inc/dec
Initialization:-• It is the first expression of loop header.
• In this expression, loop control variable is initialized.
• It is terminated by statement terminator.
• It is an optional part.
This part runs only for one time in the first iteration.
Condition:-
• After initialization, control is transferred to the conditional part.
• In this part, given condition is evaluated.
• If the condition is true, body of the loop is executed.
• If the condition is false, body of the loop is ignored and control is transferred to the statement which comes after the body of the loop.
• It is necessary for the condition of the loop to get false, otherwise loop becomes infinite loop.
• It is terminated by statement terminator.
Inc/Dec:-
• It is the third expression of the loop header.
• After executing the body of the loop control is transferred to this expression.
• This part is responsible to make the condition of the loop false.
• After inc/dec, condition is again tested.
Syntax Of for Loop:-
for(initialization;condition;inc/Dec)
{
--------------- //Body
---------------
}
Conditional Loop:-
• It is a control structure which is used to repeat set of statements until given condition is satisfied.
• There are two types of conditional loop
i. While Loop
ii. Do-While Loop
while Loop:-
• It is a conditional loop.
• It repeats set of statement until given condition is satisfied.
• It is possible in while loop, not to execute body of loop even for one time.
• It is also called top tester because it checks the condition at top and then execute the statements.
• If the condition is true, body of the loop will be executed.
• If the condition is false, body of the loop will be ignored.
• Inc/Dec expression is written inside the body of the loop.
Syntax Of while Loop:-
Initialization;
While(condition)
{
--------------- // Body
Inc/Dec;
}
do-While Loop:-
• It is a conditional loop.
• It repeats set of statement until given condition is satisfied.
• It is called bottom tester.
• It executes the body first and then checks the condition at the last.
• In this loop, body is executed at least one time.
• Two keywords are used in it
i. do
ii. while
• do represents the start of loop.• while represent the end of the loop.
• while statement contains the condition and it is terminated by statement terminator.
• If the condition is true, control is transferred to the start of the loop.
• If the condition is false, control is transferred to the next statement after the loop.
Syntax Of do-while Loop:-
Initialization;
Do
{
-----------------
-----------------//Body
Inc/Dec;
}
while(condition);
Sentinel Control Loop:-
• A loop which uses sentinel value to end the loop is called sentinel controlled loop.• A value which ends the loop is called sentinel value.
e.g:- [Y/N]
• It is normally a conditional loop.
Iteration:-
Get a value
Compare it with sentinel value.
If the value is sentinel, it terminates the loop.
If the value is not sentinel, then get the next value again.
Nested Loop:-
• Loop within the body of another loop is called nested loop.
• Nesting can be performs up to any level.
• Nesting increases the complexity of the program.
• Any loop can be placed within the body of another loop.
• For every iteration of the outer loop, inner loop runs completely.
• Outer loop controls the number of rows.
• Inner loop controls the number of columns.
Syntax Of Nested Loop:-
Loop( )
{
loop( )
{
-------------------
------------------
----------------- // Body Nested Loop
}
}
• It is the collection of variables, stored in a contagious portion of the memory having same name and same data type.
• Each portion of the memory is called element of the array.
• Each element is accessed by a unique number called subscript or index.
• Index always starts with 0.
• Range of index is = 0length-1.
Continue Statement:-
• This statement is normally used within the body of the loop.
• When this statement is executed, all the remaining statements are ignored and control is transferred to the start of loop for next iteration.
Syntax of continue statement:-
Following syntax is general syntax of continue statement.
for(a=1;a<=10;a++)
{
--------------
--------------
continue;
-----------------
--------------
-----------------
}
goto Statement:-• This statement is used for un-conditional transfer of control from one place to another place in the program.
• Normally this statement is not preferred in the program.
Syntax Of goto Statement:-
Following syntax is a general syntax of goto statement.
-------------------
------------------
--------------
goto lable;
-------------
------------
lable:
-----------------
-----------------
---------------------THE END
________________________________________
________________________________________________________________________________
0 comments:
Post a Comment