Video: Loops in C# (Bulgarian)

Topics covered:

• What is a Loop?
• Loops in C#
  • while loops
  • do … while loops
  • for loops
  • foreach loops
• Special loop operators
  • break , continue , goto
• Nested loops

Video (in Bulgarian)

Presentation Content

What Is Loop?

• A loop is a control statement that allows repeating execution of a block of statements
  • May execute a code block fixed number of times
  • May execute a code block while given condition holds
  • May execute a code block for each member of a collection
• Loops that never end are called an _infinite _ loops

How To Use While Loop?

• The simplest and most frequently used loop
• The repeat condition
  • Returns a boolean result of true or false
  • Also called loop condition

Using Do-While Loop

• Another loop structure is:
• The block of statements is repeated
  • While the boolean loop condition holds
• The loop is executed at least once

For Loops

• The typical for loop syntax is:
• Consists of
  • Initialization statement
  • Boolean test expression
  • Update statement
  • Loop body block

The Initialization Expression

• Executed once, just before the loop is entered
  • Like it is out of the loop, before it
• Usually used to declare a counter variable

The Test Expression

• Evaluated before each iteration of the loop
  • If true , the loop body is executed
  • If false , the loop body is skipped
• Used as a loop condition

For Loops

• The typical foreach loop syntax is:
• Iterates over all elements of a collection
  • The element is the loop variable that takes sequentially all collection values
  • The collection can be list, array or other group of elements of the same type

What Is Nested Loop?

• A composition of loops is called a nested loop
  • A loop inside another loop

C# Jump Statements

• Jump statements are:
  • break , continue , goto
• How continue works?
  • In while and do-while loops jumps to the test expression
  • In for loops jumps to the update expression
• To exit an inner loop use break
• To exit outer loops use goto with a label
  • Avoid using goto ! (it is considered harmful)

Summary

• C# supports four types of loops:
  • while
  • do-while
  • for loops
  • foreach loops
• Nested loops can be used to implement more complex logic
• The operators continue , break & goto can control the loop execution