28 lines
1.7 KiB
HTML
28 lines
1.7 KiB
HTML
<p>
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Almost every program or algorithm needs some kind of <b>conditional branching</b>. It is used to control the flow of your program.
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The most common form in any programming language is the if-statement or sometimes called if-then-else-statement.
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It is used to define parts of your code, which are only executed, if certain conditions are met.
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</p>
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<p>
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The if-statement consist of the keyword <b>if</b>, followed by an expression and then followed by a statement.
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The statement can be a normal statement as seen before or more commonly a block statement, which is just a group of statements treated as one. They are opened and closed by curly braces.
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If you want to define behavior, for when the condition is not met, you follow your if-statement up with an else-statement.
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</p>
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<p>
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The if-statement works by evaluating the expression. If it is true, it will execute the following statement, if not, it will jump over
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it to the next statement.
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</p>
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<p>
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Because C has no boolean values by default, any non zero value will be interpreted as true and all zeros to false.
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This can be useful. E.g if you want to check for null-pointers, you only have to put the pointer into the statement.
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But it can be dangerous to. The compiler won't warn you, if you forget to use any boolean operators.
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</p>
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<p>
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Normally you form your expression with boolean operators(<b>==</b>,<b>!=</b>,<b><</b>,<b>></b>,<b><=</b>,<b>>=</b>)
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and logical operators (<b>!</b>,<b>&&</b>,<b>||</b>). But as mentioned before you don't have to use them.
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Sometimes it is easier and shorter to use the fact that any non zero value is true.
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</p>
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<p>
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Read trough the following examples and do the comparison task in the end of the file.
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</p>
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