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| − | (Vic, Roger, David)
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| − | ==An Introduction==
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| − | Until now all your programs have been working from top to bottom. Imagine if you were to write a game to guess a secret number from 1 to 100. The entire program would consist of one hundred [[Control Structures#The If Statement|if statements]] to account for each turn to check and see if the number chosen is correct; a situation like this is where a loop will come in to play and reduce those one hundred statements into one.
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| − | A loop is a [[Control Structures|control structure]] that allows you to repeat the same sequence of code as long as a given [[test condition]] evaluates to true. Every passage through this sequence of code is called an ''iteration''. If you repeat the same sequence of code 20 times, then you have performed 20 iterations.
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| − | ==Types of Loops==
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| − | *[[While Loops|while]] -Vic
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| − | *[[for]] -Roger
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| − | *[[nested loops]] -Roger
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| − | ==[[Test_condition|Test Condition]]==
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| − | Loops use the test condition to decide whether or not to enter the body of the loop.
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| − | ==[[Scope]]==
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| − | Everything within the body of the loop is considered to be in the scope of the loop. In the case of a for loop, any variable declared in the inializer is considered to be within the scope of the loop. Declaring a variable within the variable within the scope of a loop is highly discouraged. This variable would be difined again everything time the loop iterates, causing a significant waste of memory.
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| − | ==Infinite Loops==
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| − | An infinite loop is any loop that continues to repeat forever. There are situations where this is useful, but if you didn't intentionally program it in, then it causes a '''fatal''' error for your program. These occur if the test condition in your loop will never be false. Here are a few examples of infinite loops:
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| − | <pre>
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| − | while(true) //always true
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| − | }
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| − | ------------------------------------------------
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| − | for(int i = 0; i < 20; i++) //counter reset to 0 every time
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| − | { | + | |
| − | i = 0;
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| − | } | + | |
| − | ------------------------------------------------
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| − | for(int i = 0; i < 9999999999999999; i++) //integers can't be as big as 9999999999999999, so 'i' will overflow to negative
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| − | {
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| − | } | + | |
| − | </pre>
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| − | ==[[Additional Information]]==
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| − | *[[Additional Information#Multiple Control Statments|Multiple Control Statements]]
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| − | *[[Additional Information#Do-While Loops|The Evil Do-While Loop]]
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| − | *[[Additional Information#Running Totals and Sentinel Values|Running Totals and Sentinel Values]]
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| − | ==[[Loop Review Questions and Exercises|Review Questions and Exercises]]==
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| − | Here you will find some Review Questions and Exercises to help you understand and and learn to use loops.
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