CMPSC 201 Exam 1 Flashcards

Question

Interpreted Languages

Answer 1

each command is interpreted and executed as program is run (MATLAB, Python, etc.)

Answer 2

written in the form of zeros and ones, can be understood directly by the computer

Answer 3

Source Code - Preprocessor - Compiler - Linker - Executable Code

Answer 4

Source file created by a text editor *.cpp

Answer 5

Modifies source code by instructions (#) A library of already written source code

Answer 6

Translates to Machine Code *.obj and checks for syntax errors

Answer 7

Combines various object code files to create an executable file *.exe

Answer 8

reserved words that have a special meaning. (often shown in blue)

Answer 9

words or names that have been defined by the programmer. May be variables, constants, or functions/routines.

Answer 10

tell the computer to perform specific operations.

Answer 11

begins or ends a statement, or separates items of a list.

Answer 12

grammar rules for combining elements.

Answer 13

code does not follow the grammar rules of language. Found by the compiler.

Answer 14

results are not what was expected due to incorrect implementation. (Note different from text!) Use test data for which you know what the results should be.

Answer 15

program causes the computer to perform an illegal operation. (Note different from text!) Divide by 0 or square root of negative number.

Answer 16

data the user of the program will need to enter into the program

Answer 17

information the user expects to receive from the program.

Answer 18

what the program does to the input to produce the output. Examples: Calculate weekly pay Calculate the area of a rectangle

Answer 19

Preprocessor Directive; comes before everything else in the program except the explanatory comment at the top

Answer 20

Follows #include

Answer 21

All Algorithms are programs, but not all programs are algorithms

Answer 22

CPU gets, from main memory, the next instruction in the sequence of a program's instructions

Answer 23

The instruction is encoded in the form of a number, The control unit decodes the instruction and generates an electric signal

Answer 24

After decoding the signal is sent to the correct part of the computer and causes that component to perform an operation

Answer 25

Controls and manages the basic operations of a computer

Answer 26

enhance the computer's operations and safeguards data

Answer 27

makes the computer useful for everyday tasks. Games, browsers, word, etc.

Answer 28

happen before the main function but after "using namespace std;" for global usage Format: const data type identifier = value;

Answer 29

The main function that holds all of the code be sure to use BRACES

Answer 30

happen first within the int main function and set variables for your program

Answer 31

Marks the end of the program and lets the computer know to stop

Answer 32

input for which the programmer knows the result

Answer 33

Branch, Loop, Sequence, Functions

Answer 34

some statements may be executed only when a specific condition is met.

Answer 35

statements are repeated

Answer 36

a group of statements are executed at various times in the program

Answer 37

statements are executed in order they are written

Answer 38

describe what the program is supposed to do and what various portions do. Often used as documentation. Not executed.

Answer 39

directions to perform before program starts.

Answer 40

group of statements to perform a specific task.

Answer 41

actions executed by the computer.

Answer 42

beginning of a single line comment

Answer 43

Go around a multiline comment

Answer 44

beginning of a preprocessor directive

Answer 45

enclose filenames or data types

Answer 46

contains parameters for functions or changes order of operations.

Answer 47

enclose a group of statements.

Answer 48

ends a C++ statement

Answer 49

Preprocessor directive Causes contents of another file to be inserted into the program. Often the files are library files that contain specific definitions. Not C++ statements

Answer 50

C++ is one so Include is not the same as INCLUDE or include.

Answer 51

All C++ programs must have a function main int main ()

Answer 52

cout "c" + "out"

Answer 53

cout object, the insertion operator(s) (<<), and variables or constants to be displayed. cout <<“Hello”;

Answer 54

<< insertion operator Ex: cout<<“The volume is ” <

Answer 55

Performs specific output tasks when enclosed in quotes. (cout is still needed)

Answer 56

Causes cursor to go to next line

Answer 57

Causes cursor to go to next tab stop

Answer 58

Causes computer to beep

Answer 59

Causes backslash to be printed

Answer 60

Causes single quote to be printed

Answer 61

Cause double quote to be printed

Answer 62

Inserts blank lines in output just like the escape sequence. cout << radius << endl << volume; radius volume

Answer 63

Blanks may be inserted by enclosing the spaces in quotes. cout << radius << “ ” << volume; radius volume

Answer 64

names (or symbols) used by the programmer to refer to items such as variables, named constants, functions, classes, etc. should be descriptive of what they stand for.

Answer 65

Cannot be a reserved word (keyword) only can contains letters, numbers, or the underscore. first character must be a letter or underscore (better to be a letter).

Answer 66

names for memory locations in RAM.

Answer 67

refer to memory locations in which the value stored may change throughout the execution of the program.

Answer 68

refer to memory locations in which the values do not change.

Answer 69

statements that tell the computer to allocate memory space and what identifier will be used to refer to that space. you must define or declare a variable or constant before you may use it.

Answer 70

data type variable name; where the variable name must follow the identifier rules.

Answer 71

determines how the data will be stored and what types of operations can be performed on this data.

Answer 72

Integers (whole numbers), Real Numbers (may have fractional parts), Characters (letters or numbers that you do not want for arithmetic operations), and Boolean (true or false)

Answer 73

memory spaces that will store whole numbers

Answer 74

short 2 bytes unsigned short 2 bytes int 4 bytes unsigned int 4 bytes long int 4 bytes unsigned long 4 bytes long long int 8 bytes

Answer 75

Used to store real numbers, numbers with fractional parts

Answer 76

float 4 bytes single precision numbers double 8 bytes double precision numbers long double 10 bytes

Answer 77

refers to the number of digits that are stored before the values are rounded.

Answer 78

data that is either true or false False is represented as 0 in the computer. True is represented as 1. Anything other than 0 (zero) is considered to be true. Written: bool

Answer 79

Written: char holds a single character value two methods to store multiple characters: C-strings or string objects.

Answer 80

arrays (collections) of characters. The number in brackets should include space for the null character. Ex: char variablename[n]; Can be assigned a value at time of declaration however the assignment operator does not work later.

Answer 81

# include variables that have be declared of the string class. To use the string class, you must employ the preprocessor directive. string variable name; You do not need to know how many characters need to be stored. Can use assignment operator name = “Tom”;

Answer 82

Occur before main function and will be the same value to all functions (for constant declarations)

Answer 83

Declaration only applies to that variable or constant within the function it is defined You should usually define, declare, the variables at the beginning of the function (for now main) in which they occur.

Answer 84

int alpha, beta, gamma, delta; double weight, feet;

Answer 85

store values in the memory locations.

Answer 86

= (Not the same as equals)

Answer 87

Named constants must be assigned at the time they are declared. Assignments to variables can occur at the same time as declaration or after. EX: int numberincase = 12; The left and right side cannot be interchanged! X = 5; (valid) is not the same as 5 = X; (Not Valid) The left-hand side must be a single variable.

Answer 88

It gets truncated 4.57 => 4

Answer 89

Reminder a variable declared as char can only store 1 character (letter, digit, special character)! To store more than character you must use a string (character array). ‘w’ is a single character whereas “w” is two characters (w and the null character). char var1 = ‘w’; char var1 = “w” // invalid var1 = ‘r’; var1 = “r”; //invalid char str1[2]=“q” ; char str1=“t”; //invalid

Answer 90

a collection of characters. two methods of creating strings in C++. C-strings, String objects (requires the string class)

Answer 91

manipulate numeric values and perform arithmetic operations. Classified as unary, binary, or ternary based on the number of operands needed.

Answer 92

one operand -a

Answer 93

requires two operands. X + Y c / b

Answer 94

three operands

Answer 95

+, -, *, /, % things like that

Answer 96

+ Addition sum = y + x - Subtraction diff = x - y * Multiplication numb = c * b / Division rate = part / total % Modulus remainder = d % 4

Answer 97

Integers operated on by integers result in an integer Floating points operated on by integers or floats result in floating points

Answer 98

Defines the order in which operations are performed.

Answer 99

Operations in parentheses are performed first Unary negation * / % multiplication, division, modulus + - addition and subtraction Operations of equal precedence are performed in order they are written from left to right.

Answer 100

int ==> 4 float ==> 4.0

Answer 101

A single assignment statement may be used to store the same value in multiple variables at one time. x = y = h = d = k = 4.0; Could be used to replace the statements x = 4.0; y = 4.0; d = 4.0; h = 4.0; k = 4.0;

Answer 102

cin object and extraction operator to read data from keyboard and store in memory locations. cin>> variablename;

Answer 103

when white space (space, tab, newline) is encountered.

Answer 104

separated by extraction operators. cin>>x>>y; //data is stored in order given

Answer 105

cin does not confirm data type. A char variable only stores one character (letter, digit, or special character). Using cin will allow the extraction of 1 character from the input stream. If more than one character are entered, the first is stored in the variable and the rest remain in the input stream. White spaces are skipped.

Answer 106

Remember a C-string is an array of characters and may be declared as char varname[n]; char last[12]; You can use cin to store characters in this C- string. cin>>last; Input will stop is a white space is encountered. There is no check for number of characters.

Answer 107

C++ does not check for data being within range of data type. How the data is stored may be compiler dependent. In many compilers, the number will “wrap”. For example, given the following statements short x = 32767; x = x + 5; cout<< x<

Answer 108

Automatic conversion of a data type for mathematical operations or assignment. int alpha = 10.5; // 10.5 is coerced to 10 double beta = 4; // 4 is coerced to 4.0 alpha = alpha/beta; //two coercions occur //10 is coerced to 10.0 for the division //the value 2.5 is truncated to 2 for assignment. beta = alpha * 4.4;

Answer 109

Code specifies the conversion of the data type for the purposes of an operation. Type casting a variable will not change what is stored in a variable

Answer 110

static_cast(variable or expression) data type (variable or expression) (data type) variable or expression Last two methods considered out of date

Answer 111

Assignment statement Input new value

Answer 112

Utilizes a preprocessor directive to associate a value with a word. The data type is not needed because no memory space is allocated. No memory space is used. The preprocessor will replace the word with the value. (Similar to find and replace in word processing) Because no memory is used, the data type of the value is not needed.

Answer 113

#define identifier value EX: #define tax_rate 4.5

Answer 114

Provide a shortcut for assignment statements. Combines the = operator with another arithmetic operator

Answer 115

is equivalent to a = a + 5.67; a %= 3; is equivalent to a = a % 3; Reminder---the % operator only works for integer data types.

Answer 116

is equivalent to a = a – 6.0;

Answer 117

is equivalent to a = a * 3.4;

Answer 118

is equivalent to a = a /2.1;

Answer 119

is equivalent to a = a % 3; Reminder---the % operator only works for integer data types.

Answer 120

a library file, like cmath, with a function defined that has the format of Ex: pow(base, exponent) pow(x,y) is equivalent to x^y... Use the include preprocessor directive to tell the program to incorporate the library file #include

Answer 121

that the angle is in radians not in degrees

Answer 122

The rand( ) function is used to generated random numbers, how the numbers are generated in the same order each time the program is run. cout<

Answer 123

Used with random values to skip the first “seed” values. Can use another built-in function time( ) to generate a value for the seed. unsigned seed = time(0); //generate a value srand(seed); // skip seed values cout<

Answer 124

cstdlib library file

Answer 125

The random number can be limited to a range using arithmetic principles. y = rand( ) % value + 1; // numbers from 1 to value will be generated For example, to generate numbers from 1 – 15 y = rand( ) % 15 + 1;

Answer 126

include Random number engine random_device // one engine type random_device Myrandgen; //defines an engine

Answer 127

uniform_int_distribution randInts(0,100); Object Type states how numbers will be distributed, Object name (Number range (min value, max value))

Answer 128

Use the object to store a generated number int number number = randInts(Myrandgen);

Answer 129

controls the number of spaces that will be used to output an item cout<

Answer 130

used to control the number of significant digits or, if used with the fixed manipulator, the number of decimal places that will be displayed for a floating-point number. cout<

Answer 131

set to show the decimal point and zeroes for numbers like 45.0

Answer 132

left - sends output left justified right - sends output right justified Can use more than one manipulator at a time, just separate with the << operator. The programmer can also change manipulators within the same cout statement. Ex: cout<

Answer 133

cout.width(5) instead of cout<

Answer 134

can use cin.width(n) or cin>>setw(n) However, input still stops when a space or tab is encountered.

Answer 135

To store “white spaces”, spaces, tabs, and/or returns, in char variables use cin.get( ). It has the format cin.get(varname) Often can be used to stop the program until the user enters a return If storing in a character array (C-string) the format may be expanded to cin.get(varname, n, ‘char’)

Answer 136

To store multiple characters, including spaces, in string objects. getline(cin, strname); Input stops when a newline character, ‘\n’ is encountered. Will store leading spaces as well.

Answer 137

Used to skip over characters that you do not want to be stored anywhere. Has the format cin.ignore(n, ‘char’) where n is the number of characters to be skipped and char specifies where skipping should stop. Skipping stops whenever the one of criteria is met. If char stops input, the char remains in the input stream so it may input.

Answer 138

Given test data the programmer should be able to predict what is stored in each variable at each line of code.

Answer 139

expressions that evaluate to true or false. They may be comprised of a bool variable or constant; or a combination of variables and constants using relational and/or logical operators. Relational expressions are used for both selection and repetition control structures.

Answer 140

Used to compare, or relate, two values (variables or constants) May be used with string objects, but not with C-strings (character arrays)

Answer 141

Arithmetic Operators

Answer 142

Statement(s) are executed when a condition is true. “Simple If ” or “single branched if” if (condition) { statement(s) }

Answer 143

If more than one statement is to be executed, braces must be used. Otherwise only the first statement is part of the if. Statements that belong to the if should be indented.

Answer 144

Sometimes we would like to take one action if a condition is true and another if the condition is false. Use If/Else structure if (condition) { statement(s) //to be executed if true } else { statement(s)//to be executed if false }

Answer 145

<= and >= respectively

Answer 146

No, in C++ relational operators only evaluate 2 operands

Answer 147

Combine or negate relational expressions Rewrite the expression 5 < x < 10 using the logical operator and (&&) as 5 < x && x < 10 (note that both relational operators must have 2 operands) Logical operators have lower precedence than relational operators.

Answer 148

List possible combinations plus the resultant true/false values from logical operators

Answer 149

&& higher than || Can always be overridden by parentheses

Answer 150

When the result of a combination of relational expressions can be determined from the evaluation of the sub-expression to the left of the logical operator, the sub-expression to the right is not evaluated. (x < y) || (x > z) x > z will not be evaluated if x 5) && (c < j) c < j will not be evaluated if y>5 is false

Answer 151

One method to allow for multiple branches is the if/else if structure. if (condition 1) { statement(s) } else if (condition 2) { statement(s) } *** MORE AS NEEDED******** MORE AS NEEDED***** else // default or trailing else, no if! { }

Answer 152

Go down the ifs one by one As soon as the statements associated with a true condition are executed, the branch structure is exited. When none of the ifs evaluated to true, the statements associated with the trailing else (when there is one) are executed.

Answer 153

if (condition 1) { statement(s) if (condition 2) { statement(s) } else { statement(s) } } else { statement(s) } if inside an if statement Proper indentation is very important for the person reviewing the program.

Answer 154

Because of how floating-point numbers are stored in memory, unpredictable results may occur when trying to determine equality. Stick to using greater than or less than operators and use logical operator to determine a range. Example suppose you thought the round off error to cause a 0.0000003 difference in the value (x == 4.5673675) (x > 4.5673671) && (x < 4.5672679)

Answer 155

C-strings cannot be compared using relational operators, but instead the strcmp( ) function (requires cstring library file). Has the general format strcmp(str1, str2) Compares each character by subtracting the ASCII value of str2 character from str1 character from the beginning of the strings until a difference is found. Returns a zero if strings are the same, a negative number is str1 is less than str2, or a positive number if str1 >str2.

Answer 156

refers to where an identifier (often a variable name) association is known.

Answer 157

NOT PERMITTED in this course

Answer 158

If blocks are nested, the inner block can define (declare) a new variable with the same name as a variable in the outer block. Each variable will have its own memory space. (Don't do this though it makes it hard to debug)

Answer 159

The switch has a controlling expression that is evaluated and matched to a series of cases. The controlling expression if evaluated to an integer or single character. Switch is an alternative method to treat multi-branched decisions. A variable or expression will determine which branch will be executed. switch (integer expression) { case const1: statement(s) case const2: statements(s) case const3: statement(s) case constn: statement(s) default : statement(s) }

Answer 160

switch (expression) { case answer1: statement(s) break; case answer2: statement(s) break; case answer3: statement(s) break; default: statement(s) } The answers will be constants

Answer 161

ends the execution of statements for each case. If the break statement is omitted for a case, execution will continue using the statements for the next case until a break is encountered.

Answer 162

Acts as a trailing else The default case does not have to be included. If the default is not included and no cases match the expression, no statements will be executed.

Answer 163

The “look” of the switch may be easier to understand because it looks more like a menu.

Answer 164

Cannot easily do irregular ranges. Cannot match strings.

Answer 165

adding one to a variable A = A + 1 This statement can be replaced by the incrementing operator ++. A++; (post incrementing) or ++A; (pre incrementing)

Answer 166

Subtracting one from a variable A = A -1 This statement can be replaced by the decrementing operator --. A--; (post decrementing) or --A; (pre decrementing)

Answer 167

Determines when the incrementing (or decrementing occurs), before or after the value is used. Effects the results when the variable is combined with other values.

Answer 168

Loops allow a group of statements to be executed over and over again. All loops must have: loop-control variable(s)loop-control variable(s) body - block of statements to be executed repeatedly a way for the loop to be terminated. Three basic loop mechanisms: while, for, and do-while. Loops may be classified as pre-test or post-test.

Answer 169

while (relational expression) { statement(s) // body of loop } The statements comprising the body of the loop will be executed until the relational expression evaluates to false. Therefore one of the statements should modify the loop-control variable(s) so the loop terminates.

Answer 170

Not reaching the termination condition - loop never ends. It is an infinite loop. Missing braces - only first statement is executed as body of the loop. A semicolon at the end of while line while (condition); No statement is executed - it is an empty loop and an infinite loop if the condition is true.

Answer 171

do { statement(s) // body of loop } while (condition); //test The do-while loop is a post-test loop. The condition is tested after the loop is executed once. May be sentinel or count-controlled.

Answer 172

indefinite/ the number of repetitions of the loop are not known

Answer 173

number of repetitions of the loop is already known when starting the loop

Answer 174

for(initialization; test; update) //header { statement(s) // body } Pretest loops Count-controlled (usually)

Answer 175

One, two, or all of the expressions may be omitted from the for loop. for( ; x < 10 ; x = x+2) the initial value of x is taken from earlier part of code. for( ; x < 10 ; ) the loop control variable must be updated in the body of the loop to avoid an infinite loop. for( ; ; ) // do NOT use in this course! loop is terminated in some other manner.

Answer 176

The program may initialize or update a number of variables in the for header. for(initialization(s); test; update(s)) { statement(s) } for(x = 0, sum=0; x <= 20 && sum <150; x++, sum += x) { statement(s) } Be careful! Update occurs after body of loop has been executed.

Answer 177

Should the loop always execute at least once? Yes => do-while No => while or for Should the loop be count controlled or sentinel controlled. Count => any of the loops Sentinel => while or do-while (usually).

Answer 178

a repeated comparison of the number to the current maximum value. If the number is greater than the maximum value, then the maximum value is reset to that number. There are two common ways to initialize the value of maximum: set it equal to the first value, or set it equal to an extremely low value.

Answer 179

You want to input/output data faster than by hand and/or don't want to just output the data to the stream.

Answer 180

abstract data type for file input

Answer 181

abstract data type for file output

Answer 182

abstract data type for both input or output (Not allowed in the course!)

Answer 183

datatype object name; ifstream infile; // infile is just an identifier ofstream outfile; // outfile is just an identifier Can declare multiple objects: ifstream infile, datain, filein; ofstream outfile, dataout, fileout;

Answer 184

infile.open(“filename”); outfile.open(“filename”); may specify a directory path by placing it in quotes as well infile.open(“C:\\somename.ext”); Template: ObjectType.open("filename")

Answer 185

infile.close( ); outfile.close ( ) ;

Answer 186

Put actual name in quotes. infile.open(“filename”); // in same directory infile.open(“cse103/myfile.txt”); /* other directory */ The filename may also be stored in C-string (char array) or string object. infile.open(stringname); /* stringname is character array or string object that contains the file name information */

Answer 187

like cin infile >>alpha; and cout outfile << beta; All the formatting for cout and cin will work with your file objects as well.

Answer 188

Declare File Object Associate File with Object Use File Object

Answer 189

if(!file) (lol your lab)

Answer 190

The fail function returns a 0 or false if the file has been opened correctly and a 1 or true if there was a problem. if (indata.fail( ) ) { cout<<“There is an error\n”; }

Answer 191

There is more data than you want to process by hand in a repetitive manner.

Answer 192

State of the Extraction Operator and eof function of the input object

Answer 193

The extraction operator (>>) returns a true or false based on whether the value was read correctly. When the end of find is reached the extraction operator will return a false. Therefore the successful input can be used as a status to complete the loop. while(infile >>number)

Answer 194

infile.eof( ) which evaluates to false as long as the end of the file was not detected and to true when it was detected. while (infile.eof( ) == 0) { statement(s) more input from file }

Answer 195

helps organize code, make it easier to port from program to program – modular programming; and can call the same function from many places in the program.

Answer 196

Function Definition - Function Call - Function Declaration (Prototype)

Answer 197

code for the specific task. (In this course function definitions should occur after main)

Answer 198

statement that directs control of the program to that function

Answer 199

identifies the function name and requirements. Usually occurs before main so the name is globally defined. Required for this course!

Answer 200

return type function name (data type parameter(s)) { statement(s) //function body return 0; (Not needed when return type == void) }

Answer 201

Cannot be nested inside on another. Therefore, because main is a function itself, they may be placed before main or after main (requires a function prototype). For this course you are required to put the functions after main and to use function prototypes (declarations).

Answer 202

Occur before main. Look similar to function heading except that it ends in a semicolon and it does not require the parameter name(s), just the data type(s). void print2lines ( ); int sum2int (int , int ); If the parameter name is included, it is ignored. Function prototypes are required for this course.

Answer 203

//comments # include library files function prototype(s) int main ( ) { statement(s) return 0; } function definition(s) { statement(s) // body }

Answer 204

is the statement that tells the function to execute. When execution of the function has been completed, flow of the program returns to immediately after the call. It has the format of function name (parameter(s)) The parameters (arguments) from the call are transferred to the function heading in the order in which they appear.

Answer 205

A function can call another function or even itself. y = sum2ints(5,sum2ints(pow(x,3), j)); A single C++ statement may call more than one function. xyz = cos(theta) + sum2ints(a,b); Function calls can be part of a condition. if (sum2ints(alpha, beta) > 10)if (sum2ints(alpha, beta) > 10) if (boolfunction) //function with return type bool

Answer 206

The parameters in the function heading are referred to as “formal parameters”. The parameters in the function call are referred to as “actual parameters” or arguments. When the function call is executed, the values in the actual parameters are transferred to the formal parameters.

Answer 207

What is this function supposed to do? Is the function going to send information back to where it was called? If so, what is the data type of this information What parameters does this function need to operate and what are the data types of these parameters? What variables need to be declared within the function itself?