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In this lecture you will learn about the conditional statements.

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So a conditional statements allows you to make decisions in your programs.

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So these decisions rest on building expressions.

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So which evaluate a true or false.

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So for example, you can compare some operators such as greater than or not equal to build to build

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a Boolean expression.

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So some basic comparison operators.

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Let's create an here, for example, integer.

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Let's create an integer value variable.

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Name x here and assign it to zero and 42 equals here.

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I will I will write all of this codes here and we'll explain later here.

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4 to 2, not equals to zero.

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Here.

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And 109 X here.

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One, two, three.

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Greater than or equal to X here.

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And minus ten.

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Less than X here.

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And -99 less than or equal to X here.

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So let's let me write this here.

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This is the equality operator.

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Bit further term boolean or false.

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This is the inequality operator Inequality.

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And this is his actual allotment.

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Use the tabs here.

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Okay.

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One, two.

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This is a nuclear operator here.

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This is greater than.

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And the.

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This is less greater than.

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Greater than or equal to.

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Here.

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This says less than and this is less than or equal to.

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Operator.

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Click here.

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So this program produce no output.

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Let's compile it and show what it will produce.

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This will return zero because we are not a parent.

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We are printing nothing here and using no variables here, as you can see.

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See lion automatically assign them, assign not them, not them as unused variables.

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So while the program doesn't produce any output compiling it helps to verify that your written is valid.

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C++ code.

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So to generate more interesting programs, you use conditional statements like if your SO and if statement

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contains a boolean expression and one or more nested statements.

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So depending on whether the boolean value is a true or false, so the program decides which nested statement

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to execute.

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So there are several forms of statement, but basic logic here is you use a boolean expression version

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and then statement.

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Your statement.

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Or, for example, statement here.

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So as an expression, let's create a bull type here.

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Boolean expression.

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Test.

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Test here.

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Assign it true.

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So if this boolean expression is true.

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Purely an expression.

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So if this boolean expression is true, then our statement will be executed.

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So as a boolean expression.

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So let's create a bool here.

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A You can write this as a boolean expression here, so let's put it here.

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And as you can see here, we got no error here.

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So if here print F or C out STD or let's just use print F.

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Yeah.

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If a f.

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We have to enter the variable here.

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We use this studio here because this printf contains this, printf has this studio has the printer function

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in it.

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So this, as you know, printf is not default just system method in C++ here.

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So let's create create an executed or.

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Yeah.

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Thanks.

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Here.

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And let's run this code.

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As you can see, we got no output here because our Boolean expression is false, as you can see here.

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And if we put this, if 42 equals 42, this will evaluate true.

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That's why our code will be executed.

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Here we have another point.

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Another if statement.

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You can write this like compound statement because sometimes you will want a group of statements to

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run rather than a single statement.

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If you do a single statement, you can use this as follows.

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So such a group is called the compound statement.

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So to declare the compound statement, simply wrap the group of statements in a brazier like this so

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you can use compound statements with within the if statements as follows here.

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So let's create an A here or let's get another Boolean expression.

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So if 100 is a Boolean, be here, if 100 is greater than

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100 is greater than X.

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Here, here.

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Let's make it look nice.

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Yes.

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Here and here.

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So.

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Okay.

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So if B will our B variable is if this expression will return the grid true, then our if function if

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statement, if statement will be executed.

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If not, this is not a function.

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This is a statement here.

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So let's create let's give this as an example.

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If B.

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Is true.

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If it's true, then printed this year, for example, code.

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Executed.

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S.F. executed.

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Quote to.

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Pier, code one and executed code here and use this.

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So let's use this.

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And as you can see here, let's actually add new line.

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So make it look nice.

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Here.

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So executed Code one.

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Executed code two.

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So in this case, our both this statement is executed.

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So actually, let's make this comment to.

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So if the comment is, as you know, the compiler will not compile this code and use this as a command,

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just a text here.

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As you can see, the both of our functions, both of our expressions and codes is executed in this if

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statement.

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So if we if this values true, or we can use this and directly give this as an here, if 100 is greater

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than X, then execute our code.

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As you can see, we got that same output.

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So if we change to use less than operator here, this function, this code will not this if statement

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will not execute.

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As you can see here, the x equals zero.

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So our 100 is not less than zero.

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And this if statement, we will not execute in this time.

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So you can elaborate if statement using the ls if and l statements here.

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So this optional addition allows you to describe more complicated branching behavior.

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So let's create another example here.

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If so, make it here.

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And if our boolean expression is true, then use the statement.

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Print F.

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My statement.

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One new line.

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And here else if.

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Our my statement.

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My statement is true.

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My statement.

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This is this is an expression we have to give here if false or let's actually use the create a new variable

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integer.

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My var variable here is hundred and integer.

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My my.

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My car and my van here is 50 and integer.

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My.

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My phone is, for example, ten, just as an example variable names.

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So if our my car.

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Is greater than zero.

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Actually, we don't need these variables here.

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Then evaluate my car.

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Greater than greater than 100.

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Here.

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And then if this statement is not executed, you lose the.

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My car and give the second statement.

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If my car equals greater than actually make this 50 and my car is greater than 50, and then you give

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this my car.

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Greater than 100.

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Yeah.

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Hundreds.

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And then else and else.

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We don't have to give condition here.

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Then if these conditions will not exceed good, then use this else condition here and you're going to

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write it here.

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We don't know about what or just values.

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As statement here.

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If and else if statements does not executed here and our SE comment is executed here and use this here.

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So let's run this program and execute it code my car greater than 50 here as you can see here, our

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car my car is equal to zero.

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My car is equal to 100.

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And that's why this ls If command is not executed.

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And let's create an let's assign my car 101.

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And as you can see here, my car is greater than 50 here.

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So if we do like the little else here and use this and as you can see, both of our expression expressions

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will be executed here.

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Make it nice.

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So like my car greater than 50, my car greater than 100.

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So the first boolean expression here is evaluated here.

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Actually, let's make it evaluated.

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So if boolean expression one is true and then statement one is evaluated and if statement stops executed

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and if boolean expression one is false, then boolean expression two is evaluated.

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So.

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If true this statement to hear.

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If boolean expression two is true, then the our statement two will be executed.

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Otherwise statement free will be executed.

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So if you make it like one, then our.

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Excluded.

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Court to hear actually if integer my car and else else if.

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Here, so you can include any number of URLs if classes.

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Or omit them entirely.

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So as with the initial if statement, the boolean expression for each else if class is evaluated in

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order.

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So when one of these boolean exploration evaluates to true evaluation stops and corresponding statement

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executes.

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So if no else if course evaluates to true the else here statement tree will always execute.

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So now I want to write some quote here.

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So integer, create an integer here or let's value make my card variable zero in here.

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Then if our my car greater than zero, then here print my car, my car greater than zero here or less

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here.

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And as if here.

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If my car less than zero then print.

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Print test.

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Negative.

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My car.

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My car.

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Less than zero.

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And F statement here.

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My car print off my car equals to zero.

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So now we can run this program and see what happens.

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Let me.

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So as you can see in this case, my card is zero.

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So if a sign and this if statement is executed, as you can see here.

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So if we make it more why my car to.

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Then my car greater than zero, will execute us well if we make it minus one.

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Then my card less than zero here.

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This statement is executed.

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If I make it zero again, then the SE statement my car equals to zero will be executed.

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And that's it.

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But the C++ conditional statements here.