WEBVTT

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Welcome, In  this lecture I'm going to show you how flexible "for" statement is. and at the end  you'll learn

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about the break statements.  Lets get started.

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Remember this "for" statement.

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Now I'm going to tear it apart, in a good way of course and the break statement will naturally emerge

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from its ashes.

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Let's do that!  Now, remove the initialization statement

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It can also work this way.

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Assume that the i variable is declared somewhere before and outside of the "for" statement.

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Notice the separator.

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It's still there right.

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So Go can understand that there are still a condition and a post statement. ok lets continue.

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Now I also removed the post statement.

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this works too.

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offcourse I needed to increase the "i" variable myself.

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Otherwise the loop will never quit.

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I moved it after the summation.  It's because I'm trying to imitate the actual "for" loop here.

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Remember Go runs the post statements after running all the statements in its block. So that's why I'm

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incrementing

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the "i" variable at the end of the loop here.

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Notice again the separators

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they are still here right.

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OK let's also remove the separators.

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This is known as the "for" statement with a single condition.

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Now let's also remove the condition. here

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this loop will never quit. It will loop forever to the infinity Its because behind the scenes the condition

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is still there! it's just hidden and it equal to true. remember for loop will continue as long as its

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condition is true.

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right? so because the hidden condition is true this loop never quit.

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By the way this loop syntax is called an infinite loop.

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As you see in the examples that infinite loops are mostly used when you don't know how many times you

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would repeat the statements.

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For example you can keep repeating the loop until the user presses the quit key.

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Or you can use it for a network server.

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which runs and listens for ever.

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So how can you end  this for loop.

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Let me show you. To exit from the loop.

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I need to use a break statement. but where you type the break statement is very important because it will

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break out from the loop immediately.

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For example, if you call it here. it will quit from the loop after the summation and it will skip the following

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incr-decr statement.

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So because of this! Actually, This loop will end  on its first step.

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and I don't want that. I want to add the numbers as before. right?

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So you need an  If statement to properly quit from the loop.

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Let me show you

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now I'm going to type an if statement like this.

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As you can see I move the break statement inside the if statement now.

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This way the loop will only quit after the "i" variable becomes greater than 5. right?

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Let me show you this.

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In the code editor.

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first I'm going to declare the sum and "i" variable's like this since I want to add the numbers starting

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from 1 so I've initialized the "i" variable to 1

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OK then I'm going to type an infinite for statement like this.

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Just the curly braces right here.

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Inside this block, I'm going to compare whether the i variable is greater than 5 or not like this.

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So this way this program will only add numbers up to 5 and I'm going to type break statement here.

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So it will quit from the loop only when  the i variable becomes greater than 5 and then I'm going to

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add the "i" variable to the sum variable like this and lastly, I'm going to increment the "i" variable

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The order of the statements is very important. as I said it's like the actual for statement now.

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So before each loop step begins go we'll check for the condition then it will add the "i" variable and the sum.

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Then at the end it will increment "i" variable and the loop will continue until the "i" variable becomes greater

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than 5.

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Then it'll break out from there.

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All right.

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Now let's run this

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as you can see it prints 15, which is just correct.

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Now let the me print  the numbers here.

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So you can see what it's calculating. println i 

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dash dash

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greater than arrow and sum. OK?

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OK let me run into again.

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So it adds the numbers

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step by step right.

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All right in the next lecture I'm going to show you another statement

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If these examples look simple to you don't worry at all. I  prepared more challenging ones as well.

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You'll learn about them soon

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So see you in the next lecture.

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Bye Bye