WEBVTT

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In this lecture you will learn about the conditional statements.

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

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So these decisions rest on boolean expressions 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 world to build

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a boolean expression.

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So some basic comparison operators, let's create an here for example, integer, let's create an integer

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value variable named X here and assign it to zero and 42 equals here.

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I will I will write all of these quotes here and we'll explain later here.

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42 not equals to zero.

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Here and the 100 greater than X here.

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One, two, three.

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Greater than or equal to X here and minus ten less than X here.

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And -99 less than or equal to X here.

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So let let me write this here.

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This is the equality operator.

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It will return boolean or false.

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This is the inequality operator.

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Inequality.

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And this is here.

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Actually, let me use the tabs here.

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Okay.

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One, two.

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Three.

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This is a unique operator here.

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This is greater than and.

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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 is less than and this is less than or equal to operator.

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Here.

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So this program produces 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 apparent.

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We are printing nothing here and using no variables here.

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As you can see, Sea Lion automatically assign them, assign not the note them as unused variables.

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So while the program doesn't produce any output compiling, it helps to verify that you are written

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as valid plus plus code.

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So to generate more interesting programs, you use a conditional statements like if here so an 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.

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So the program decides which nested statement to execute.

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So there are several forms of if statement.

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But basic logic here is you use the boolean expression question and then statement.

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Your statement.

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Or, for example, statement here.

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So as Boolean expression, let's create a bool type here.

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Bool 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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Boolean 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.

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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, um, or let's just use print f.

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We're.

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If a print f.

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We have to enter the variable here.

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Okay.

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We use this studio here because this printf contains this printf has this studio has the printf 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 plus plus here.

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So let's create an executed or.

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Yeah.

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X 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 another if statement.

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

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to run rather than a single statement.

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If you do 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 braces here like this

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

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

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So if 100 is Boolean, be here.

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If 100 is greater than it, 100 is greater than X here.

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Here.

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Let's make it look nice.

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Here.

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Here and here.

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So.

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Uh, okay.

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

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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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A, if B.

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Is true, evaluates true.

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Then print F this year for example.

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Code.

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Executed.

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Printf.

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Executed.

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But to.

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Here code one and executed code two.

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Here.

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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.

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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 two.

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

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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 quotes is executed in this

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if statement.

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So if we if this value is 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 get the same output.

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So if we change to use less than operator here, this function, this code will not x 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 will not execute in this time.

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

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So these optional additions 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 and 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 a this is a Boolean expression we have to give here if false or let's actually use the create

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a new variable integer.

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My var variable here is 100 and integer.

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My my.

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My car here is under and my van here is 50 and integer my.

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My phone is, for example, ten.

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This is just 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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But actually, we don't need these variables here.

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Then evaluate my car greater than greater than 100.

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Here.

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And then if this statement is not executed, use the.

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My car and give the second statement if my car equals greater than.

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Uh, actually, let's make this 50 and my car is greater than 50.

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And then you give this my car greater than 100.

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Here.

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Hundred.

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And then else.

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And we else we don't have to give condition here.

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Then if these conditions will not execute, then use this else condition here and we're going to write

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it here.

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We don't know about what or just evaluates.

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S statement here.

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

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So let's run this program and executed code my car greater than 50 here.

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As you can see here, our car, my car is equals to zero and my car is equals to 100.

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And that's why this else if command is not executed 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 delete the URLs here and use this.

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And as you can see, both of our expression expressions will be executed here.

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We'll make it nice.

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So my car greater than 50.

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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 the if statement stops

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executed 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 if Boolean expression two is true, then the statement two will be

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executed.

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Otherwise.

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Statement three will be executed.

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So if you make it like one, then our.

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Executed code two here actually if integer mcar.

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And else.

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Else if.

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Here.

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So you can include any number of else if classes or omit them entirely.

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

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in order.

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

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executes.

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So if no else if evaluates to true the else here, statement three will always execute.

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So now I want to write some code here.

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

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Then if our my card greater than zero then here print f my car, my car greater than zero here or here.

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And else if here.

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If my car less than zero, then print f.

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Print F 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 else statement here.

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My car print f my car equals to zero.

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

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Actually, let me.

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

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So if we assign and this if statement is executed, as you can see here.

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So if we make it more my card to.

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

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Then my card less than zero.

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Here.

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This statement is executed.

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

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And that's it.

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About the C plus plus conditional statements here.