WHAT IS LOOP:
“Loop is a mechanism that allow us to
do the task again and again just by writing once”.
Where looping is the continuous repetition of
a statement or a block of statements. But for the looping some work have to do that's we will have
to initialize the loop, put conditions and do increment or decrement to the loop.
INITIALIZATION:
Initialization, it is a part of loop in which
we initialized the variable that explained that from where the loop will be
start. To do this we assigned a fixed value to the variable like suppose a is
variable then use a = 0;
CONDITION:
In this part of loop
we explained what the condition at which the loop stop looping. To do this we have
to put condition to the variable by considering above example a<=10. This
mean the iteration will stop when the given condition become false. Condition
can be called as Boolean condition.
INCREMENT/DECREMENT:
The last part of
looping, in which we increase the variable by a fixed value or decrease, this
part explained that by end of each iteration how many value will increase or
decrease. It can be made by two methods which is
a.
Pre –increment or decrement
operator
b.
Post –increment or decrement
operator
PRE-INCREMENT OR DECREMENT
OPERATOR:
“This operator increase
or decrease the value by one before assigning the value to the variable”. It means
that first increase/decrease the value and then assigned the value to the
variable.
Syntax:
++variable name And --
variable name
For example, suppose a is desired variable now do it.
++ a or - - a
POST-INCREMENT OR
DECREMENT OPERATOR:
This operator first assigned the value to the variable
and then increase and decrease by one or by given value.
Syntax:
Variable name ++ Or Variable-name = Variable name + required
value And
Variable name - - Or Variable-name = Variable name - required
value
For example, suppose
a is desired variable now do it.
For increment (a ++, a = a+5 or a = a+4 etc.)
For decrement (a - -, a=a-5 or a=a-4 etc.)
LOOPING:
“The continuous repetition of any
statement or block of statement is called looping”.
This type of program is come in the iteration statement
program type. Where we have three type of statement program type that is.
1.
Sequential statement
2.
Conditional statement
3.
Iteration statement
TYPES OF LOOP:
Three type of method is used for looping.
1.
For loop
2.
While loop
3.
Do while loop
4. Foreach loop
FOR LOOP:
“For loop is a control flow statement
which is used for repeating a statement or block of statements, when the number
of iteration is predefined”.
SYNTAX:
for (initialization; condition;
increment/decrement)
{
Statement
or block of statement;
}
Note that if only
one statement execute under the control of loop no need to write the statement
in between braces. Otherwise the statement must enclose in braces.
Example program:
·
Program that print number
from 0 to 10.
#include<stdio.h>
void main (void)
{
int a;
for (a=0; a<=10;
a++)
printf (“%d,”, a);
getch ();
}
WHILE LOOP:
“While loop is a control flow
statement use for looping when the number of iteration is not pre-defined “.
It’s mean that this
operator is use when we have to do iteration infinite time. But also it can use
for the predefine iteration. Below is an example of this.
SYNTAX:
initialization;
while (condition)
{
Statement
or block of statement;
increment/decrement;
}
Example program:
Do above program
using while loop.
#include<stdio.h>
void main (void)
{
int a;
a=0;
while(a<=10)
{
printf (“%d,”, a);
a++;
}
getch ();
}
DO-WHILE LOOP:
“Do while loop also a control flow statement use for iteration. It executes
the block of code at least once”.
It is used when the statement under control of
loop should execute at least once, and then repeatedly execute of the block of
statement or not depending upon the given Boolean
condition.
Syntax:
Initialization;
Do
{
Statement or block of statement;
Increment/decrement;
}while(condition);
Example program:
Do above program
using do while loop.
#include<stdio.h>
int main ()
{
int a;
a=0;
do
{
printf("\n
I love myself");
a++;
}while
(a<=10);
getch();
}
FOREACH LOOP:
“The foreach loop in C iterate a block of code on each element in an
array or a collection of item”.
Foreach (element in iterate able-item )
{
Body of foreach loop;
}
NESTED LOOP:
“Loop in a loop is called nested loop”
If in any program
loop is used in a loop then that will called nested loop.
Example syntax:
for (initialization; condition;
increment/decrement)
{
for
(initialization; condition; increment/decrement)
{
Statement or block of statement which has to
execute under control of for loop;
}
}
Example program:
Write a program that
prints,
1
1 2
1 2 3
1 2 3 4
1 2 3 4 5
#include<stdio.h>
void main (void)
{
int a, b;
for (a=1; a<=5;
a++)
{
printf(“\n”);
for (b=1; b <= a;
b++)
printf(“%d”, b);
}
}
 |
| Looping in C, C++ |
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