CS 1325 EXAM 1
How do you dereference a pointer?
*ptr = 10
How do you initialize a pointer?
*ptr = 10;
What are C program file names should end with?
.c
What are the phases of compilation-based execution of a C prorgram?
1. Edit 2. Preprocess 3 Compile 4. Link 5. Load 6. Execute
What are some examples of manipulations that is done to the program before compilations?
1. Including other files in the files to be compiled 2. Performing various text replacements 3. Defining various macros
What does a valid identifier in C can consist of?
1. Letters (lower and upper) 2. Underscores 3. Digits
What are the three types of constants?
1. Literals 2. #define preprocessor directives 3. use of the const declaration on a variable
What are good rules for a variable names?
1. Use capital or underscore to create multi word identifiers 2. Abbreviations should be long enough to clearly indicate what is being abbreviated 3. Avoid the use of generic names 4. Don't create several variable names that differ only by one or two characters
What are the three things that we must know how to do before using a pointer?
1. define a pointer 2. initialize a pointer (giving it a value) 3. Dereference a pointer
How many bytes are in a long double?
10 bytes
How many bytes are in a float?
4
How many bits is in a byte?
8
How many bytes are in a double?
8
What happens during the linking phase?
A linker links the object code with the code for the missing functions to produce an executable image
What is a literal?
A literal is a constant value that is written into the program
How many significant figures can a single precision float store?
About 6-7
What is the name of this operator --> '&' ?
Address operator
What does the edit phase of a C program has to be accomplished by?
An editor program
Why can't the object code be executed?
C programs typically contain references to functions defined elsewhere , therefore the object code contains "holes".
What produces the object code?
Compiler
What is a dynamic data structure?
Data structures that can grow and shrink at execution time
T/F: '$' is a valid identifer
False
T/F: C has pass by reference
False, C does not have pass by reference but pass by value only
T/F: C program are typed in with the linker.
False, C program are typed in with the editor and corrections are made if necessary
T/F: A pointer does not need to be defined before they can be used
False, a pointer must be defined before any use
T/F: Character literals are always in double quotes
False, character literals are always single quotes
T/F: After the source code is turned into an object code it is complete and executable?
False, the object code is not complete and not yet executable
What is a preprocessor directives?
Indicates that certain manipulations are to be performed on the program before compilation
'*' is a _______ operator
Indirection operator or dereferencing operator, is applied to a variable outside of a declaration and returns the value of the object to which its operand points
What happens in C11 when you use the nullptr keyword?
Initialized the pointer to 0
What does the loader do?
Takes the executable image from disk and transfer it to memory
What executes the object code?
The CPU
What does a pointer contain?
The address of a variable that contains a specific value
During step 3 (after the preprocessing steps) what happens to the C source code?
The compiler translates the C modified source code into object code and stores it on the disk
During stage 2, preprocessing, who gives the command to compile the program?
The programmer
Consider the following code: int x=5, y=10; swap (x,y); void swap (int a, int b) { int temp = a; a = b; b = temp; } T/F: This function swap the values of x and y?
This function will swap a and b (parameters), but not x and y (the arguments).
How many sizes does a floating point data type comes in?
Three
T/F: pointers read right to left
True
T/F: yptr = &y; assigns the address of the variable y to pointer variable
True
T/F: A char can also be interpreted as a small integer
True
T/F: A variable name directly references a value, and a pointer indirectly references a value
True
T/F: ANSI C standard , an identifier can be of any length
True
T/F: An identifier cannot duplicate a reserved word
True
T/F: Before C-11, you can use the constant NULL to initialized the pointer to 0
True
T/F: C is case sensitive
True
T/F: Double precision double and long double precision long double has 8 bytes
True
T/F: Literal values does not change
True
T/F: Literals are not associated with a named location in memory
True
T/F: Short int has 2 bytes
True
T/F: Single precision float has 4 bytes
True
T/F: Strings in C are represented as arrays of characters terminated by a null (\0)
True
T/F: The address operator (&) is a unary operator that returns the address of its operand
True
T/F: The first character of an identifier must not be a digt
True
T/F: There is no string class in C
True
T/F: Unsigned integers stores twice as large as the signed integer of the same type (and size)
True
T/F: Use of leading underscores is discouraged for general use
True
T/F: int (16 bit) has 2 bytes
True
T/F: int (32 bit) has 4 bytes
True
T/F: int *c, b; "c is a pointer to int" or "c points to an object of type int"
True
T/F: int numOfStudents is an example of a variable declaration
True
T/F: Given: int *c,b; The ' * ' only applies to c in this definition. The variable b is still just a plain integer
True
T/F: int *c, b; specifies that variable c is of type int* (a pointer to an integer)
True
T/F: int *countptr, count; is an example of a defining a pointer
True
T/F: printf("%d", *yptr) prints the value of variable y and it is called dereferencing a pointer
True
T/F: #include <stdio.h> #define <identifier> <replacement text> are examples of preprocessor directives
True
T/F: Before the program can be executed, the program must first be placed in memory
True
T/F: Character literals are enclosed in single quotes
True
T/F: Compiler will only look at the first 31 characters of an identifier
True
T/F: During linking, multiple object files might be combined into one executable
True
T/F: In a C system, the preprocessor executes automatically before the compiler's transition phase begins
True
T/F: Pointers can be defined to point to objects of any type
True
T/F: Variables can be declared and initialized in the same statement
True
T/F: long int has 4 bytes
True
T/F: There are no boolean data type in C
True, Boolean evaluation are done through integers (0 = false and non-zero value = true)
T/F: In the previous ANSI C standard, all variable declarations in a function must be initiated before any executable statements
True, but this was changed by C99
What do you use to define a pointer?
Using an asterisk before the variable name.
How do you declare a single byte in C?
Using char (data type) keyword
What are constants?
Values that cannot be changed during the execution of a program
What are the four standard data types in C?
Void, characters, integers, and floating point data types
How many significant figures can a double precision double store?
about 14 - 15
What are the three sizes of a floating point data type?
float, double, long double
How do you define a pointer?
int * ptr;
What produces the executable code?
linker
What places the program in memory?
Loader
What is a variable?
Named locations in memory that contain a value
What does a void return?
Nothing
What are floating point literals?
Numbers with decimal values
What are integer literals?
Numbers without decimal values
What is an object code?
Object code is essentially a machine code, a binary file that consists of a series of 1's and 0's?
How many bytes is a char?
One byte
What does a pointer enable a program to do?
Pass functions between functions, and to create and manipulate dynamic data structure
What are pointers?
Pointers are variables whose values are memory addresses
What produces the modified source code?
Preprocessor
What kind of "special commands" does the C preprocessor obey?
Preprocessor directives
What does indirection mean?
Referencing a value through a pointer
What does a char usually represent?
Represents a value from the ASCII table
How can the "holes" be resolved in a C program?
Resolved by the linker
Where is the program stored?
Secondary storage device such as a hard disk
What produces the source code of a C program?
Source code is entered with a text editor by the programmer
What does C provide to return the size of any data type in bytes?
sizeof( )
