CSE 2421 - Systems 1 Exam 1 Review
True
A block in ANSI C can legally be empty
Memory leaks
A condition where the memory used by the program may grow potentially without bound
True
A const keyword variable must be initialized as part of the declaration
Nibble
A group of 4 bits at a time
spaces
BASH uses ______ as a a tokens separator
True
C allows direct manipulation of memory
\r
Carriage return character
\f
Formfeed character
True
In ANSI C, all variable declarations in the block must precede the first non-declarative statement (ie no-just-in-time declaration in C)
Machine code
Is C fully compiled to machine code or byte code
Procedural
Is C procedural or object-oriented
Invalid
Is ca$h a valid identifier name?
Yes (keep in mind that both Unix/linux use the _ to start many variable names)
Is the identifier name _counter valid?
\n
New line character
.o
Object files that the computer reads use what extension
\ooo
Octal number character
True
The pre processor prepares a .c file for the compiler
Precedence
The relationship between two operators in terms of the order in which the operations are preformed
True
There are 2 basic data types in C: integer data types and floating point data types
False (The potential derived types made from basic types is infinite)
There is no way to create any data types other than the 2 basic data types
0101
a = 10 = 1010 What is ~a
1010
what is a ^ c a = 10 = 1010 c = 0 = 0000
1010
what is a | c a = 10 = 1010 c = 0 = 0000
1011
what is a | c a = 10 = 1010 c = 1 = 0001
1011
what is a | c a = 10 = 1010 c = 3 = 0011
0000
what is a&c a = 10 = 1010 c = 0 = 0000
0000
what is a&c a = 10 = 1010 c = 1 = 0001
0010
what is a&c a = 10 = 1010 c = 3 = 0011
1101 0100
x = 0111 0101 What is x << 2
1111 1101
x = 1111 0101 Arithmetic x >> 2
0011 1101
x = 1111 0101 Logical x >> 2
\\
Backslash character
\xhh
Hexadecimal number character
\t
Horizontal tab character
The compiler ignores them
How is white space (tabs/newlines/returns, spaces, etc.) handled within a C program file?
8
How many bits are in one byte?
8
How many bits is a char
64
How many bits is a long
128
How many bits is a long long
16
How many bits is a short
32
How many bits is an int
8
How many bytes is a double
16
How many bytes is a long double
4
How many bytes is a single precision floor at
Style
IS an identifier name of camelBack a requirement or a style (i.e. do we have to capitalize?)
True
Preprocessor takes input from sourcecode.c and output goes to sourcecode.i
True
Preprocessors replace any MACROs
True
Preprocessors strip all comments from .c files
\?
Question mark character
-2^(w-1) to 2^(w-1)-1
Range of binary two's complement (B2T)
Arithmetic shift
Shift used when interpreting as signed values
Logical Shift
Shift used when interpreting as unsigned values
\'
Single quote character
.c
Source code files in Unix/Linux have what extension
0 to (2^w)-1
What is the range of integers in unsigned binary (B2U)
After
a++ is when a is incremented ________ a is evaluated in the expression
It was developed to create the UNIX system.
Why was the C programming language initially created?
Valid
is printf a valid identifier name?
1 11 3 1 12 -1 5 11 -2 5
#include <stdio.h>int main() { int z, a=10, b=0, c=3; z = (++a > b) || (++a < c++); printf("z = %d, a = %d, c = %d\n", z , a, c); /* 1. z= HERE a= HERE c= HERE */ c = 30; z = (a > c) || (++a > --b); printf("z = %d, a = %d, b = %d\n", z, a, b); /* 2. z= HERE a= HERE b= HERE*/ a = 10; c=3; z = ++a + --b * c++; printf("z = %d, a = %d, b = %d, c = %d\n", z, a, b, ++c); /* 3. z=HERE , a= HERE, b = HERE, c = HERE */ return(0); } Enter answers separated by a single space, there should be 10 answers
Before
++a is when a is incremented _________ a is evaluated in the expression
both return type and parameter information
A function declaration contains: - no return type information, just parameter information -both return type and parameter information - no return type or parameter information - return type info, bur no parameter info
return type and parameter information plus code body
A function definition contains: - no return type information, just parameter information - no return type or parameter infor - return type info, but no parameter infor - return type and parameter information plus code body
Type information only, no initial value
A variable declaration contains: - both type and initial value information - no value or type information - type information only, no initial value - no type information, only an initial value
both type and initial value information
A variable definition contains: - both type and initial value information - no value or type information - type information only, no initial value - no type information, only an initial value
True
ANSI C does not have a Boolean type
#
ANSI C preprocessor directives begin with: - // - # - /*
False (Classes and Objects are C++ constants, not C constructs)
ANSI C supports the notion of Classes and Objects
\a
Alert (bell) character
True
All L-Values must be modifiable since they are assigned a value
False (functions have file scope in C)
All functions have block scope
Both logic errors and division by zero
An example of a dynamic error is: - Both logic errors and division by zero - Division by zero - Syntax error - Logic error -Both Syntax and logic errors
Syntax Error (A static error would either be a syntax error or a linking error)
An example of a static error is: - Incorrect file name - Syntax error - Division by zero
No
Are any two identifier names that are identical for the 1st 31 chars a good choice?
\b
Backspace character
False
C has garbage memory collection
Function
C statements grouped into a single logical unit
True
Const variables are treated as read-only variables
\"
Double quote character
Compile time
Events that can occur when a program is being compiled or built
Run time
Events which can occur when the program is being executed or running
True (This is true and similar to the requirement that a C++ program must have one main() method.)
Every C program must have exactly one function called main()
Macros
Fragments of code, defined in the source file, or in a header file, with the code they are defined to represent Created with the #define preprocessor directive
File scope
If a function is declared in a file, that function can be used anywhere within the file after it is declared. - declaring a function - block scope - file scope - false
file1 file2 file3
If the command line says: lab1 < file1 >file2 2>file3 then, stdin comes from ANSWER stdout goes to ANSWER stderr goes to ANSWER
file1 Screen Screen
If the command line says: lab2 <file1 then, stdin comes from ANSWER stdout goes to ANSWER stderr goes to ANWSER
Keyboard file1 file2
If the command line says: lab3 >file1 2>file2 then, stdin comes from ANSWER stdout goes to ANSWER stderr goes to ANWSER
file1 screen file2
If the command line says: lab4 <file1 2>file2 then, stdin comes from ANSWER stdout goes to ANSWER stderr goes to ANWSER
keyboard file1 file1
If the command line says: lab5 > file1 2>&1 then, stdin comes from ANSWER stdout goes to ANSWER stderr goes to ANWSER
keyboard file1 screen
If the command line says: lab6 2>&1 > file1 then, stdin comes from ANSWER stdout goes to ANSWER stderr goes to ANWSER
keyboard file1 file 2
If the command line says: hello >file1 2>file2 then, stdin comes from ANSWER stdout goes to ANSWER stderr goes to ANSWER
False
If we can redirect stdin when running a program within gdb we are redirecting input for both the program and all gdb instructions we want to execute
True
In ANSI C, all declarations in a block must precede the first non-declarative statement
Valid (may truncate after 31 chars)
Is California_Emission_Control_Baseline a valid identifier name
No (It's not a keyword, because C identifiers are case sensitives, but it could be confusing)
Is GoTo a good choice for an identifier name?
Style
Is an identifier name of Avg_Val a requirement or a style? (ie. are you require to use _?)
No (Identifiers in C can not contain spaces)
Is avg value a valid identifier name?
Yes (It has to be valid or we couldn't use it as a function name)
Is main a valid identifier name?
True
Modern computers store and process information as two-valued signals (off/on, true/false, 0/1)
Linux has 60-100 viruses listed compared to the 85-120 viruses listed for UNIX
Name another difference between Unix/Linux from your required reading.
True
Nest blocks are valid in C, but nested functions are invalid
False
The ANSI C compiler will treat two variables, named val and Val in a C program as the same variable.
While open source systems don't always cost money to purchase the license, it can cost money to purchase the hardware needed to run the system. Also, it takes time to learn and set up open source systems, which can cost you time. Server versions for open source systems also cost money, but this is for support contracts, not the software.
UNIX is proprietary system (i.e. you must purchase a license) while Linux is an Open Source system. An Open Source system, however, is not always "free". Why?
Arrays, pointers, structures, unions, plus the ability to use each of these vehicles recursively
Vehicles to create derived types are: - There is no ability to derive more types - Arrays, pointers, structures, unions, - Arrays, pointers, structures, unions, plus the ability to use each of these vehicles recursively
\v
Vertical tab character
True
We can redirect input to a program that we are running within gdb
Gdb
What C device allows you to: - watch your program run instruction by instruction - observe a variable change values and see when things you thought should happen don't - Give you opportunities to fix them within your code with significantly less effort
Declarations, data movement, arithmetic/logical operations, control-flow
What are the four general categories of Statements in Computer languages
Function prototypes
What do head files usually contain
The data display debugger
What does DDD stand for
The GNU Debugger
What does Gdb stand for
It tells us the number of lines of code that is in the file.
What does the wc -l instruction do? The manual page for that instruction says prints the newline count, but what important information does that count tell you?
.h
What is the extension of a header file
ASCII digits have a value 48 greater than what they represent
What is the relationship between the ASCII value of a digit and the actual value it represents?
UNIX was built around a kernel using "code recycling features," which allowed it to be more easily adapted to different types of hardware compared to other software systems.
What made UNIX different from all other commercially available software systems when it was initially developed?
LINUX
What operating system covers the widest range of hardware in the world?
False (the line that is printed out by gdb is the line that will be executed next.)
When a line of code is printed out after the next command in gdb, that line of code has just finished executing. True or False?
While running the program during testing (This is the first time that a dynamic error can be found)
When can a dynamic error first be found? - While running the program during testing - At compile time - Only after the program is deployed to a customer's location
At compilation time (Static errors can only occur during compilation)
When can a static error first be found? - At compilation time - Only after the program is deployed to a customer's location - While running the program during testing
Short circuit evaluation
When relational statements stop evaluating once a statement's value is definitive
it is a function declaration that terminates with a ';'
Which of the following is true with respect to a prototype statement: -it is a function declaration that includes code -it is a function declaration that terminates with a ';' -it is a function definition that terminates with a ';'
False (It's a reserved word so it can't be used)
goto is a valid identifier name
10 x z 14 arr1[3]
int x=10, y=20, z = 30; /* What do the statements below do? */int arr1[ 20]; int *int_ptr1, int_ptr2; int_ptr2 = arr1; int_ptr1 = &x; y = *int_ptr1; /* 1. Replace *int_ptr1 with a number, so y=HERE */ *int_ptr1 = 0; /* 2. Replace *int_ptr1 with an identifier, so HERE=0 */ int_ptr1 = &z; *int_ptr1 = 15; /* 3. Replace *int_ptr1 with an identifier, so HERE=15 */ x = *int_ptr1-1; /* 4. Replace *int_ptr1 with a number, so x=HERE */ *(int_ptr2+3) = x; /* 5. Replace *(int_ptr2+3) with an identifier,so HERE= x */ Reminders: * in a declaration says "I am a pointer" that points to a certain type of value & means "address of" * (on the right side of an assignment) means "get/read the value at that address" * (on the left side of an assignment) means "set/write the value at that address" Answers should be separated by 1 space
Invalid (In C, an identifier cannot start with a number)
is 123 a valid identifier name?
invalid (Identifiers in C cannot contain *)
is a*b a valid identifier name
