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[No Audio]

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In this tutorial, we will be covering two

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important concepts in connection with loops,

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they are called break and continue statements.

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Again you will find similar and

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equivalent concepts in almost all the

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programming languages. We will cover the

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break statement first, so let's get started.

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First I will write some suitable comments.

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[No Audio]

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Okay, the break statement is inside the loops

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for stopping the loop execution. When a break

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statement is encountered inside a loop, the

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loop is immediately terminated, and the

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program control resumes at the next statement

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following the loop body. Let us explain this

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by having a simple example. Suppose, I want

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to write a program, which given a certain

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number typically greater than or equal to 100,

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will compute the smallest number lesser than

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the given number, which is divisible by 13.

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Of course, there are many ways in which this

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program may be coded, but I will code it with

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the help of simple loop. Again, this is just

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for the sake of illustration, and the solution

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may not be the optimal solution, but the

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intent here is to learn the usage of break.

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So I will first declare a variable, which

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contains the given number. So, I will write

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let mut, and then var, and I will make it

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equal to let's say a value of 100. Next, I

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will write a simple loop by writing, loop

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followed by two curly brackets. Inside the

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loop, I will first deincrement the value of

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the variable var by one, because we are

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looking for a number which is strictly less

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than the current number, which is divisible by 13.

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So, I will write a var = var - 1.

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Next, I will check if the number

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is divisible by 13 or not. So, I will write

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var and then % sign, which is a mod operator,

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and then 13 == 0.

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Now, if the if statement is true, it will

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mean, that we need to exit from the loop,

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because we have found our desired number.

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To exit from the loop, we will use a break

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statement, inside the body of the if statement

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by writing a break. In case the condition is

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not true, we will continue with the next

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iteration, where again, the variable var will

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be reduced by a value of one, and the

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condition will be checked again. Outside the

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body of the loop, I will display the number

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which I may found inside the loop by writing

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println, followed by exclamation mark, and

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then within the parentheses, I will put two

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quotes where I will write, The highest number

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lesser than the given number divisible by 13

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is, curly brackets, var.

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The break statement inside the if statement will

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terminate the loop, once it is encountered,

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and it will shift the control to the first

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statement outside the body of the loop,

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which will be the print statement. So let us cargo run this.

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Yes, the correct answer, which is 91,

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is being displayed to us. Again please note

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that the break will move the control to the

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first statement after the body of the loop.

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Let us now learn the second topic of today's lecture.

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I will add suitable comments first,

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and will comment out the code that we have

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written so far.

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[No Audio]

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The continue statement skips the current

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iteration of the loop and continues with the

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next iteration. When the program encounters

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the continue, the continue statement, all

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the statements beneath the continue

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statement will be skipped, and the next

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iteration of the loop will be executed.

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Let us do a simple example to illustrate the

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use of continue. I will write a simple

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program in which I want to compute the first

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three numbers with the property, that they are

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divisible by both 3 and 5. The program

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will start with the number 0, and will

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keep on incrementing it by a value of one, and

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keep on checking for the property. We know

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that the first such number will be the number 15,

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and the second number is 30, and the third

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number is 45. When the first three numbers

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are found with the proposed property, the

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program should stop processing further

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numbers. Let us start implementing this program.

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I will start by declaring a variable

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var with a value of zero, so I will write

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let mut var: i32 = 0.

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This variable will be incremented sequentially and

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will be checked for the required property.

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Next, I will declare another variable, which

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will keep on counting the numbers with the

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property. So, I will write let mut count : i32 = 0.

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Next, I will declare an

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infinite loop by writing, loop followed by curly brackets.

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During each iteration of the

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loop, I will first increment the variable

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var by one, so I will write var = var +1

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Next, I will check if the

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current number under investigation has the

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property or not, so I will write var %

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sign, followed by a value of 5 == 0.

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And then since I am

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looking for another condition also, so I

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will write &&, and then

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followed by var % 3 == 0.

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Inside the if body, I will add a

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print statement by writing println

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followed by exclamation mark, and then

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within the parentheses, I will put two quotes

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where I will write the number which is

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divisible by both 3 and 5 equals to, curly brackets,

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and then followed by /, var.

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This statement will be

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printed each time I found the number with the

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property. Next, inside the same if body, I will

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add one to the value of count, by writing

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count = count +1. Next, inside

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the if statement, I will check if the value

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of the count is equal to 3 or not,

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because when it reaches the value of 3,

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I want to quit the program, because I intend to

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find the first 3 numbers with the property.

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So, I will write, if count == 3,

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and then within the curly

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brackets, I will write break. Next,

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outside the body of the outer if statement, I

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will add a simple print statement which will

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print the current number under investigation

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by writing println

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exclamation mark. And then within the

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parentheses, I will put two quotes, and inside

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the two quotes, I will write curly brackets, var.

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This means that, during each

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iteration of the program, I will first

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increment a variable var, and then we'll

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check the condition. And if the condition is

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satisfied, I will print this message followed

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by this print, and then at this condition.

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Let us cargo run this program, and then we

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will refine its output by making use of the

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continue statement. Okay, you may note that we

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have the number that is being printed. And

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when the condition is being met, we have the

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special output afterwards, the program again

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starts to print the numbers starting from the

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value of 15. This looks a bit bad, because we

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already have a special print statement for

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the value of 15. Now, we want the program to

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skip printing the value of 15, and in the same

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way, after the value of 30. Let us see how we

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can skip printing the values of 15 and 30.

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The if statement we see that, when the

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count == 3, the loop is being terminated.

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However, when the count is

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not equal to three, then the loop continues

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with the remaining statements beneath the if statement.

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That is, it keep on executing the

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statement of the print statement. If we write

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after the if statement, else, and then within

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the curly brackets, continue, the program will

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not continue with the remaining of the

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statements in the loop, and will not print the number.

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This means that, when the outer if

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statement is true, the inner if will get a chance.

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If in that case, the inner if is true,

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the loop will terminate. However, in case

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when it is not true, the else part will be

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executed, which will skip the execution of the

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current iteration, thereby, avoiding the print

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statement beneath it to get executed, and will

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shift the control to the next iteration.

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Let us cargo run to check, if the desired output

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is being achieved by making use of the

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continue statement. Yes, we may note that, the

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value of 15 and 30 are not part of the

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printed values anymore. In some sense,

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the continue has some similarities with the break.

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However, instead of forcing termination

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of the entire loop, it forces the next

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iteration of the loop to take place,

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skipping any code coming after the continue in the

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same iteration. There is a special use of the break,

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when used in association with loops.

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It can also be used to return a value from

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that loop. This is only valid with simple loops,

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and not with any other type of loops,

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such as for loops or while loops. For

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instance, if in the same program, I want to

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return the third value with the property, that

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it is divisible by both 3 and 5.

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So I will write something like, something like,

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let req_number = loop at the top.

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Next, when I use the break,

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which basically exits from the loop, I will

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mention the variable name, which I want to

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assign to the req_number,

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which in this case will be the variable of var.

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So I will write break followed by the

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variable name var. Outside the body of the

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loop, I will add semicolon. Let us add a

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print statement outside the body of the loop

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for displaying the value of the variable

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req_number, by writing println

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followed by a exclamation mark, followed

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by parentheses, and then within the two quotes

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I will write the required third highest

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number divisible by both 3 and 5 is,

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curly brackets, req_number.

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Let me cargo run this, and we may note that

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the variable value has been correctly

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displayed. Please note that, this is a special

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use of the break, which can only be used when

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the break is used in connection with simple loops.

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Also note, that in the same way, is used

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with simple loops. The two constructs of

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break and continue may be used in combination

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with the for loops and while loops. The

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essential working is the same as explained,

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and the behavior will not change. Okay, that

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brings us to the end of this tutorial. I hope

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you would have enjoyed this. That also brings

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us to the end of this section, and now in the

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new section we will be coming up with more

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interesting concepts. So do come back to cover

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those. And until next tutorial, happy Rust programming.

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[No Audio]