The lecture covered decision statements and loops in C#. It discussed if, if/else, and if/else if statements for decision making based on logical conditions. It also covered for and while loops. The for loop is used when the number of iterations is known, while the while loop runs until a condition is no longer true. Key loop concepts included initialization, condition, and increment/decrement. The lecture concluded with a discussion of how decision statements and loops are important programming concepts and how attendees could apply them.

1. LECTURE 3
BY: RUBYNA VOHRA

3. AGENDA
• Decision Statements
• If
• If/Else if
• If/Else
• Loops
• For Loops
• While Loops

4. DECISION STATEMENTS

5. WHAT IS A DECISION
STATEMENT?
• Decision making structures
require that the programmer
specifies one or more conditions
to be evaluated or tested by the
program
• Along with a statement or
statements to be executed if the
condition is determined to be
true,
• Optionally, other statements to
be executed if the condition is
determined to be false.

7. LOGICAL CONDITIONS
• C# supports the usual logical conditions from
mathematics:
• Less than: a < b
• Less than or equal to: a <= b
• Greater than: a > b
• Greater than or equal to: a >= b
• Equal to a == b
• Not Equal to: a != b

8. WHEN TO USE SPECIFIC STATEMENTS
• Use if to specify a block of code to be executed, if a specified condition is true
• Use else to specify a block of code to be executed, if the same condition is false
• Use else if to specify a new condition to test, if the first condition is false
• Use switch to specify many alternative blocks of code to be executed
• Note that if is in lowercase letters. Uppercase letters (If or IF) will generate an
error.

9. IF SYNTAX
if (condition)
{
// block of code to be executed if the condition is True
}

10. ELSE SYNTAX
if (condition)
{
// block of code to be executed if the condition is True
}
else
{
// block of code to be executed if the condition is False
}

11. ELSE IF SYNTAX
if (condition1)
{
// block of code to be executed if condition1 is True
}
else if (condition2)
{
// block of code to be executed if the condition1 is false and condition2 is True
}
else
{
// block of code to be executed if the condition1 is false and condition2 is False
}

12. SHORT HAND IF...ELSE (TERNARY OPERATOR)
• There is also a short-hand if else, which is known as the ternary
operator because it consists of three operands.
• It can be used to replace multiple lines of code with a single line. It is often used
to replace simple if else statements:
• variable = (condition) ? expressionTrue : expressionFalse;

13. LIVE WALKTHRU/EXPLANATION

15. LOOPS

16. WHAT IS A LOOP?
• Loops can execute a block of code as long as a specified condition is reached.
• Loops are handy because they save time, reduce errors, and they make code
more readable.
• 2 types of loops  while and for

17. WHILE LOOP
• The while loop loops through a block of code as long as a specified condition
is True:
• Syntax:
while (condition)
{
// code block to be executed
}

18. THE DO/WHILE LOOP
• The do/while loop is a variant of the while loop.
• This loop will execute the code block once, before checking if the condition is true, then it will
repeat the loop as long as the condition is true.
• Syntax:
do
{
// code block to be executed
}
while (condition);

19. DO WHILE VS WHILE

20. LIVE WALKTHRU/EXPLANATION

21. FOR LOOP
• When you know exactly how many times you want to loop through a block of code, use
the for loop instead of a while loop:
• Syntax:
for (statement 1; statement 2; statement 3)
{
// code block to be executed
}
• Statement 1 is executed (one time) before the execution of the code block.
• Statement 2 defines the condition for executing the code block.
• Statement 3 is executed (every time) after the code block has been executed.

22. FOR EACH LOOP … TO BE CONTINUED WITH
ARRAYS
foreach (type variableName in arrayName)
{
// code block to be executed
}

23. LIVE WALKTHRU/EXPLANATION

26. DISCUSSION
• Why is this important?
• How can this be useful to me?
• How can I use this in my current
job?
• How can I use this in my future
career?
• What will I get out of this?
• How is this used in the real world
Regroup and discuss after…

28. COMPLETE THE
WORKSHEET WITH
YOUR GROUP
Regroup and discuss after…