Loops_sushma

LOOPS
By
Sushma Desemsetty

What is Loop?
Loops are used in programming to repeat a specific block until some end condition is met.
There are four kinds loops.They are:
1.for loop
2.while loop
3.do...while loop
4.nested loops

for loop
It's preferred when you know how many iterations you want, either because
you know the exact amount of iterations, or because you have a variable
containing the amount.
Syntax : for (initialization-statement ; condition; increment/decrement)
{
// code
}

for loop
How for loop works?
The initialization statement is executed only once.
Then, the condition is evaluated. If the condition is false , for loop is terminated. But if
the test expression is true , codes inside the body of for loop is executed and update
expression is updated. This process repeats until the test expression is false.

class program
{
static void Main(string[] args)
{
int number = 5;
for(int i = 0; i < number; i++)
Console.WriteLine(i);
Console.ReadLine();
}
}
Example of for loop

while loop
The while loop simply executes a block of code as long as the condition you
give it is true.
Syntax : while (condition)
{
//codes
}

while loop
How while loop works?
The while loop evaluates the condition.
If the condition is true , codes inside the body of while loop is evaluated. Then, again the
condition is evaluated. The process goes on until the condition is false.
When the condition is false, the while loop is terminated.

class Program
{
static void Main(string[] args)
{
int number = 0;
while(number < 5)
{
Console.WriteLine(number);
number = number + 1;
}
Console.ReadLine();
}
}
Example of while loop

do-while loop
The do..while loop is similar to the while loop with one important difference. The body of
do...while loop is executed once, before checking the test expression. Hence, the do...while
loop is executed at least once.
Syntax : do
{
// codes
}
while (condition);

do-while loop
How do-while loop works?
The code block (loop body) inside the braces is executed once.
Then, the condition is evaluated. If the condition is true, the loop body is executed again.
This process goes on until the condition is evaluated to 0 (false).
When the condition is false , the do...while loop is terminated.

class Program
{
static void Main(string[] args)
{
do
{
Console.WriteLine(number);
number = number + 1;
} while(number < 5);
}
}
Example of do-while loop

Nested loops
Loop can be used inside loop in any programming language including C#.
Such loops are known as nested loops.
There are three types of nested loops.They are:
1.Nested for Loop
2.Nested while Loop
3.Nested Do While Loop

Nested for Loop
Syntax :
for (initialization; condition; increment/decrement)
{
for (initialization; condition; increment/decrement)
{
statements;
}
statements;
}

class Program
{
static void Main(string[] args)
{
for (int i = 1; i

Nested while Loop
Syntax :
while (condition)
{
while (condition)
{
statements;
}
statements;
}

int i = 5;
while (i >= 1)
{
int j = 5;
while (j >= I)
{
Console.Write(j);
j--;
}
i--;
Console.WriteLine();
}
Console.Read();
Example of Nested while loop

Nested do-while Loop
Syntax :
do
{
do
{
statements;
}while (condition);
statements;
}while(condition);

Example of Nested do-while loop
int outerLoopNumber = 1;
int sum = 1;
do
{
int innerLoopNumber = 1;
do
{
Console.Write(" {0}", sum);
sum += 1;
innerLoopNumber++;
} while (innerLoopNumber

Methods of the Array Class
The Array class is the base class for all the arrays in C#. It is defined in the System
namespace. The Array class provides various properties and methods to work with arrays.
*Properties Of Array Class
*Functions of Array class

Properties
Length
Rank
Properties Description Example
Returns the length of
array. Returns integer
value.
Returns total number
of items in all the
dimension. Returns
integer value.
int i = arr1.Length;
int i = arr1.Rank;
IsFixedSize
Check whether array is
fixed size or not.
Returns Boolean value
bool i = arr.IsFixedSize;
IsReadOnly
Check whether array is
ReadOnly or not.
Returns Boolean value
bool k =
arr1.IsReadOnly;

Functions of Array Class
Function Description Example
Sort Sort an array Array.Sort(arr);
Clear
Clear an array by removing
all the items
Array.Clear(arr, 0, 3);
GetLength Returns the number of elements arr.GetLength(0);
GetValue
IndexOf
Copy
Returns the value of specified
items
Returns the index position of
value
Copy array elements to another
elements
arr.GetValue(2);
Array.IndexOf(arr,45);
Array.Copy(arr1,arr1,3);

Thank You