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34 Cards in this Set
- Front
- Back
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How are comments created in Xcode?
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// is used for comments that are contained on a single line; /* and */ are used to start and end comments that exceed a single line.
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What is the difference between a program and an application?
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A program is a set of code that causes the computer to execute instructions; an application has a graphical user interface.
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What must every code statement written in C end with?
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A semicolon.
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What is a command-line tool?
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A program with no graphical interface that runs in the terminal.
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What is a daemon?
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A program with no graphical user interface that can run for days in the background (e.g., pboard or mailer-daemon).
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What is a function?
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A list of instructions the computer is to execute. C and Objective-C programs call on the function called main when a program beings.
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Why are program comments useful?
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They can be used to document program logic, prompt programmers to return to specific program sections for debugging, etc.
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What is a program?
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A collection of functions, which are a list of operations the processor is to execute.
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What is a variable?
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A place in which data can be stored for later use in a program. The variable will have a value (e.g., 23.2).
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How is a new variable created?
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Its type must be declared (e.g., float weight;).
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Why must each variable type be declared?
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The type helps the compiler check for errors. It also tells the compiler how many bytes of memory to reserve for that variable.
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What are five of the most commonly used variable types?
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short, int, long, float, double.
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Which variable types are short, int, and long?
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Whole numbers (no decimal point).
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What variable types are float and double?
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Floating point numbers (decimal points). In memory, floats and doubles are stored in mantissa/exponent fashion (e.g., 346.2 is 3.462 x 10 squared).
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What is char?
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A one byte integer we consider to be a character, such as 'a'.
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What is a pointer?
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A pointer holds a memory address. It is declared using the asterisk. (E.g., int * holds a memory address for an int value—but not the value itself).
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What is a struct?
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A struct(use) is a type made of other types. New struct definitions can also be created (e.g., GeoLocation type can contain the two floats latitude and longitude).
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How is an if/else statement constructed?
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if (conditional) {
} else { } |
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How can true and false be expressed in if/else and similar program statements?
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False is always expressed via 0; while any number not 0 can be used for true, 1 is very common.
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What does < mean?
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The number on the left is less than the number on the right.
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What does > mean?
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The number on the left is greater than the number on the right.
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What does <= mean?
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The number on the left is less than or equal to the number on the right.
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What does >= mean?
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The number on the left is greater than or equal to the number on the right.
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What does == mean?
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The number on the left is equal to the number on the right.
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What does != mean?
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The number on the left is not equal to the number on the right.
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How do = and == differ?
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The single = means to assign value, while == refers to equality.
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What does && mean?
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The logical AND, it means that a statement is true only if both conditions are true.
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What does || mean?
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The logical OR operator, it means the statement is false only if both conditions are false.
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What does ! mean?
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The logical NOT operator, it means true becomes false, or false becomes true.
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How is logical OR different in Objective-C than in some other languages?
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There is no logical exclusive OR in Objective-C.
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What is a boolean variable?
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A variable that can be true or false.
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How is a boolean value identified in most languages, and how does this differ in Objective-C?
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Most languages use int for a boolean value; Objective-C uses BOOL (which is an alias for an integer type).
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What type of statement can be used for situations in which there are more than two possibilities?
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The else if statement.
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When is the conditional, or ternary operator used?
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Denoted by ?, the conditional/ternary operator is used whenever a value is assigned to a variable based on a conditional.
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