CS 14228 Final Exam
What is the output of the following
First Loop and Second Loop Displays employee 1 employee 2 employee 3 employee 4 employee 5 Third Loop Displays employee 1 shows shows infinitely
What is a do while loop
a 'post-test' loop executes at least once Use when the code in the loop must be executed at least one time Test a condition at the bottom
What is a while loop
a 'pre-test' Executes zero or more times use when number of repitions is NOT known in advance Test a condition at the 'top' to determine whether or not to continue loop General form is while (logical expression include input validation for interactive programs that use while loops A while loop can also be sentinel or end-of-file controlled
What are constants
constant values that are assigned to variables; values that aren't meant to change during the program's execution; however, since they are stored in normal variables, the could be accidentally be changed; therefore it is better to store these values in constant variables Named constants - named constants or constant variables must be initialized when defined; cannot accidentally be changed during program execution Identifiers - programmer-defined names of things that appear in programs such as variables, constants (literals), and function
What is a function definition?
contained the function header line and the statements that make up the function
What is the software life cycle
Stage 1 - Problem Analysis and Specification Stage 2 - Design Stage 3 - Coding Stage 4 - verification and validation stage 5 - maintenance stage 6 - obsolence
What is string data type
String library #include <string> Variable declaration General format string variable_name; Input, output, and assignment of strings work just like numeric types
How do you initilize all elemnts in an array to 0 with a loop
for (int i = 0; i < SIZE; ++i) scores[i] = 0;
How do you read data into an array
for (int i = 0; i < SIZE; ++i) { Cout << "Enter a value: "; cin >> score[i]; }
What is an assignment statement
general form is variable = expression
What are the decision making or selection control constructs
if if-else if-else if-else if-else... switch
What does a nested do-while loop look like
int main ( ) { char again; double sum = 0.0; double price; Do { Cout << "Enter the price of the item purchases: " Cin >> price; Sum = sum + price; Do { Cout << endl << "More Items? ( Enter y for yes or n for no)"; Cin >> again; } while (again != 'y' && again != 'Y' && again != 'n; && again != 'N'); } while (again == 'y' II again == 'Y'); Cout << endl << "The total of all purchases is " << sum; Return 0; }
What does a user controlled loop look like
int no_purchases Cout << "How many items did you buy? "; Cin >> no_purchases For (int 1 = 1; i <= no_purchases; ++i) Cout << "item " << i << endl;
Do the variable names of the actual arguement need to match the names of the variables dummy arguements
no, they are just given value in order of appearance call is printLarge (num1, num2); header is void printLarge (double num2, double num1) although confusing, the variable num2 that is in the function will actually be assigned the value from num1 in int main and vice versa
What is Java
object-orientated language developed at Sun Microsystems used to develop programs that run over the internet in a web browser
What does declaring a loop index variable in the for loop's initilization expression mean
only exists within loop if declared in loop
What pass can alter storage in int main and uses an &
pass by reference AKA pass by address
What pass can get a copy of the arguement from int main but cannot change the value of it in int main, only changes the value within the function
pass by value
What is short-circuit evaluation
refers to the condition where an expression is no longer evaluated because additional evaluation will change the value of said expression
What are the parts of all function definitions
return type function name parameter list (can be empty) body (enclosed in curly braces)
What is a variable definition
there are two basic types of data: numbers & characters; you must 'define' variables and what type of data the variables will hold
What is an array declaration and how is an array numbered
type array_name [SIZE] numbered from 0 to SIZE -1
What type of functions return one value to the calling routine vie a return statement?
typed function Library functions such as sqrt ( ), pow ( ), & abs ( ) all return a single value of a particular data type. The main function returns a value.
What is stream extraction operator
used for input from the keyboard of from a file >> Cin - read from the keyboard
what is a stream insertion operator
used for output to the screen or file << Cout fout
What is a sentinel while loop
value while (read) loop general form read initial value while value read is not sentinel value process the value read next value end while loop
What is a parameter or dummy arguement
variable declared in the function header line that receives an actual arguement passed to the function from the calling routine
What type of function does something but return nothing or returns multiple values to the calling routine?
void function
What is the definition of a void function with an empty parameter list?
void printColumnHeaders ( ) { Cout << "Name Hours Worked Hourly Rate";
What is a variable initilization
when a value is assigned to a variable as part of the variable's definition
What loop would work best for the following situation: A ball is dropped from a starting height. Each time the ball bounces, it returns to half the height from which it started. For a user-specified starting height (in inches), how many bounces will it take before the ball bounces to less than 1 inch in height?
while loop
How are arguements passed by position?
within the paramter
What are the expressions precedence rule
() parentheses Unary minus * / % (evaluate left to right) + - (evaluate left to right)
What is a function protype
(or function declaration) is the declaration of a function. Just as variables are declared before they are used, functions should be prototyped (declared) before they are called. Using a function prototype eliminates the need to place a function definition before all calls to a function.
What is shorthand operators
+= -= *= /= %= make sure to initialize anything that uses a shorthand operator
What are the assignment operators
= Assignment statement When the value is assigned to a variable as part of the variable's definition, it is called initialization
What are the language translators?
Assembler - software that translates assembly language code to binary machine language instructions before it is executed by a computer Interpreter - software that translates one statement at a time of a program written in a high-level language into a sequence of machine actions and executes the statement immediately before going on to translate the next statement Compiler - software that translates a program written in a high-level language into binary machine language instructions so that the program can be executed by a computer. The compiler searches along the way for syntax (grammar) errors in the program
What is CPU? ROM? ALU? Control Unit? Main Memory/Core Memory? (RAM) Auxiliary Memory? Input/Output devices
CPU - Central Processing Unit - Controls the computer and how it works. in consists of two basic parts: the ALU and the Control Unit ROM - read only memory is found in the CPU ALU - Arithmetic and Logic Unit - addition, subtraction, multiplication, division, comparisons Control Unit - controls the intruction cycle of the program - Fetch, update, decode, execute Main Memory - Core Memory - RAM - Random Access Memory - RAM is fast and expensive and provides more power Main memory is discrete and volatile in that is it easily lost when the computer is turned off and the information has not been saved Auxililiary Memory - floppy disks, hard drives, CD, DVD< flash drives, etc Input device - keyboard, mouse, scanner, light pens, optical mark readers, voice recognizers, etc output devices - monitors, printer, speaker, etc
What are the repitition/loops control constructs
Count for loops While Loops Do While loops
What are the steps for file input/output
Declare the file variables ifstream infile; ofstream outfile; Open the files infile.open ("prog0.inp") outfile.open ("prog0.out) You should use the full path to the file being opened. You must either use a forward slash or two backslashes in the path to the file (or have them saved in the same location on the computer) Read from or write to files infile >> score; outfile << average; Close the files infile.close ( ); outfile.close ( );
What is a program that returns a single bool value look like?
Function Prototype bool isOdd (int); Function Call if (isOdd(x))... Function Definition bool isOdd (int number) { bool result; if(number%2==0) result=false; else result=true; return result; }
What is a program that calculates the average of two integers and the function returns the single value
Function Prototype double averageValues (int total, int count); Note -Recall that including the names for parameters (dummy arguments) in the prototype is not necessary; however, when multiple arguments are sent, listing the names in the prototype helps indicate the order in which the arguments were listed Function Call avg=averageValues (total, count); Function Definition double avgerageValues (int total, int count) { double avg; avg = static_cast<double>(total)/count; return avg; }
What is a program that has a function that returns a value read from a file
Function Prototype double getADouble (ifstream & ); Function Call Real_number = getADouble (fin) Function Definition double getADouble (ifstream &fin) { Double value; Fin >> value; Return value; }
What is a program that has a function return a single value entered by a user?
Function Prototype double getADouble(); Function call Real_number = getADouble(); Function definition double getADouble { Double value; Cout << "Enter a real number"; Cin >> value; Return value;
What is an example of defining user defined function that return a single value
Function Prototype int sum (int, int); Function Call to a function that returns a single value Just like with the predefined math functions discussed previously, functions that return a single value are usually called as a part og an assignment statement total = sum (a, b); Function Definition int sum (int num1, int num2) { int result; result = num1+num2; return result; }
What is an end-of-file controlled while loop
General form - while ( !fin.eof( ) ) the eof ( ) function has been known to be persnickety under certain circustances there is an alternative approach General form - while ( fin >> exam_score )
What is part of a computer's hardware? a computer's software?
Hardware CPU RAM Secondary storage devices input devices output devices Software operating system applications programs
How do you check to see if input/output files opened
If (!infile) Message about termination Return 1; If (!outfile) Message about termination Return 1;
What are the simple data types?
Int - whole numbers Float (single precision), double (double precision), long double - real number Char (primarily used for storing characters but actually an integer data type, usually 8 bits Bool (set to either true or false Integer data types, sizes, and ranges
What are the expression types
Integer division (be careful) Int 5 / int 2 would be 2 no decimals no left-overs Pure expression (all values of a single type) Mixed expression The presence of a real makes everything real Type coercion to a pure expression Data type rankings (in descending order) Double Float Int In a mixed expression, the lower-ranked type is converted to the higher ranking type Overflow and underflow Each numeric data type has a max and min value when you take max + 1 you get min, when you min - 1 you get max It's all a big circle
What is an example of a program using the function printLarger with 2 parameters
Note: Recall that the variable names of the actual arguments do not need to match the variable names of the parameters or dummy arguments.
What is an example of using the function printValue with one parameter
Note: The variable name of the actual argument does not need to match the variable name of the parameter or dummy argument.
What is memory organization
Random Access Memory (RAM) Each byte has a unique address High order bit/low order bit How many unique addresses are there is each address in primary memory is a 10-bit address 2 to power 10 or 1024 unique addresses
What are the sequential control constructs
Read Write Assignment
How do you pass data to a function
Recall math functions previously examined (sqrt, pow, abs). x = sqrt ( a ); y = abs ( b ); z = pow ( 4.0, 3.0 ); the variables a and b and the literals 4.0 and 3.0 in the examples above are arguments passed to the functions. Arguments are the information needed by the function to do its job. (We will refer to these as the actual arguments.)
What are the three types of control constructs
Sequential Decision making or selection repetition/loops
What is setw? setprecision? fixed? showpoint? What library is used for these?
Setw - used for lining up columns of data; reserves a specified number of spaces for printing a value Setfill - when used with setw can be used to fill a designated field with specific characters setprecision, fixed, and showpoint manipulators Setprecision specifies the number of decimal places to be displayed Can be used to control the number of significant digits or precision with which floating-point values are displayed Values are rounded to a specified decimal place Fixed manipulator forces the digits to be printed in fixed-point notation, or decimal notation instead of in scientific notation Showpoint manipulator By default, floating-point numbers are not displayed with trailing zeros, and those without a fractional part are not displayed with a decimal point To display numbers padded with zeros, the showpoint manipulator can be used Most compilers display trailing zeros when the setprecision and fixed manipulators are used together without showpoint Setprecision, fixed, and showpoint remain in effect for all floating-point values until a new setprecision is used For floating-point value output, setw, fixed, showpoint, and setprecision are used together iomanip library
How do you pass a file variable to a function
To allow a function to write to a file or read from a file, it is not enough to simply pass a file variable to the function. An additional character, the ampersand (&), is needed when declaring the file variable parameter in the function prototype and function header line. The reasoning behind including this extra character is left for a future discussion.
What is typecasting
To avoid the implicit type coercion, you can use the cast operator. The cast operator, also known as type conversion to type casting, takes the following form Static_cast<new DataTypeName> (expression reduced to a value to be converted Expression is evaluated first then the value is converted
What are the matmatical operators
Unary operators - (negation) ex -5 Binary operators + addition - subtraction * multiplication / division (WARNING INTEGER DIVISION) % modulus operator (returns the remainder after integer division No exponentiation operator Relational operators <= less than or equal to == equal to >= greater than or equal to != not equal to < less than > greater than Stream insertion operator - used for output to the screen or to a file << Cout is to output to the screen Endl is an output manipular by simulating hitting the return key on the keyboard Stream Extraction operator - used for input from the keyboard or from a file >> Cin - used to read from the keyboard
What is a switch
Used for selecting one of several possible integer or integer compatible values when there is a small number of cases to check Break statements mark the end of if the above is true execute until you reach a break, then skip the rest
Which allows access to memory? Pass by reference or pass by value?
When an actual argument is passed to a function by reference (or address), access is provided to memory. If the function changes the value of the parameter or dummy argument, this does affect the value of the actual argument.
How are arguements passed by value?
When an actual argument is passed to a parameter or dummy argument, a copy of the value of the argument is passed. If the function changes the value of the parameter or dummy argument, this does not affect the value of the actual argument.
What are user-defined function that receive data
Writing and calling a function printValue that receives an integer value and prints that integer value to the screen:
Will for (;;) run?
Yes, but Becky doesnt like it
What is a count (for) loop
a 'pre-test' loop use when number of repitions is known in advance General form For ( Initialize loop index variable; Test logical expression; Increment or decrement ) Do not modify the loop index variable inside the loop. The result is not predictable
What is input validation?
a process of checking the validity of input data Check numbers to ensure they are within a range of possible values Check values their 'reasonableness' Check items selected from a menu or other sets of choices to ensure they are available options Check variables for values that might cause problems, such as division by 0
What is Visual Basic
a software development environment by Microsoft that allows programmers to create windows-based applications
What is C++
a spin-off of the C language also developed at Bell Labs that offers object-orientated features not found in C; portable
What is a function call?
a statement that causes a function to be executed
What is an algorithm? What are the expressions?
a step by step ordered procedure that solves a problem in a finite number of precise steps Expressions Top-down design (hierarchy chart) - start with the overall task, then break down into progressively smaller tasks (Divide and Conquer) Natural language (English-like statements) Flowchart - a diagram that shows the logical flow of a program Pseudocode - a cross between natural language and a programming language Programming Language language translators
What is a C
a structured language developed at Bell Laboratories that allows low-level programming while using a high-level language
What are variables
a symbolic name represents a location in the computer's random-access memory (RAM) used to hold a piece of information, information that may change while the program is running; variable names should be self-documenting (clearly reflecting their purpose) should be self-documenting
What is main
a typed function that returns as an integer value
What data type holds multiple values
a vector
What is using namespace std
declares that a program that will be accessing entities whose names are part of the namespace called std
What is the COBOL
designed for business applications
What is the FORTRAN
designed in the late 1950s to meet the needs of the scientific and engineering communities
What does a do while look for when used for error trapping
do { Cout << "Enter an integer between 1 and 10: "; Cin >> number; } while (number < 1 II number > 10);
What loop would also work best for the following situation: Solve the payroll problem where the input file contains an unknown number of employee records. While the employee ID#, rate of pay, and number of hours worked can be read from the file, print to an output file the employee ID# and the amount earned in table form
end-of-file controlled while loop
What loop would work best for the following situation: Solve the payroll problem where the input file contains an unknown number of employee records. Read from an input file the employee ID#, his/her rate of pay, and the number of hours worked. Print to an output file the employee ID# and the amount earned in table form. Process employee records until end of file.
end-of-file controlled while loop
What does y = y++ do? What about y = ++y?
first one displays then bumps the y value if it displayed it would display the original y value the second one bumps then does it reads add one and it asks to what and it reads the y so the y is displayed as the +1 and now stored with the +1
How do you print the value of an array to the screen with a count loop
for (int i = 0; i < 5; ++i) Cout << scores[i] << endl;
What is a program that uses a function sum and demonstrates calling a user defined function that returns a single value
int sumIntegers (int, int); int main ( _ { int num1, num2, total; cout << "Enter 2 integers: "; Cin >> num1 >> num2; total = sumIntegers (num1, num2); Cout << "The sum is " << total; Return 0; } int sumIntegers ( int num1, int num2) { int result; result=num1 + num2 return result; }
What is PASCAL
introduced the concept of structured programming & special data types; a teaching language
How do you find the largest value in an array with a loop
largest =scores[0]; // Assumes first element is the largest for (int i = 1; i < SIZE; ++i) { if (scores[i] > largest) Largest = scores[i] } Cout << "Largest value: " << largest;
What are low-level languages? High-level languages
low-level Assembly language - closer to the numeric machine language of the computer itself than to our natural language Disadvantages - machine-dependent, not close enough to natural language to be easily learned and understood, and requires a technical background High-level BASIC - met the need for simplicity; often used in an interactive environment FORTRAN - designed in the late 1950s to meet the needs of the scientific and engineering communities COBOL - designed for business applications Pascal - introduced the concept of structured programming & special data types; a teaching language C - a structured language developed at Bell Laboratories that allows low-level programming while using a high-level language C++ - a spin-off of the C language also developed at Bell Labs that offers object-orientated features not found in C; portable Java - object-orientated language developed at Sun Microsystems used to develop programs that run over the internet in a web browser Visual Basic - a software development environment by Microsoft that allows programmers to create windows-based applications
What is the BASIC
met the need for simplicity; often used in an interactive environment
What are some different ways to access array elements
scores[2] = 34; //assigns the integer 34 to array element scores[2] scores[0] = scores[2] +1; //assigns the value in scores[2] + 1 to array element scores[0] cin >> scores[4]; //read an integer from the keyboard and store it in array element scores[4] cout << scores[3]; //write the integer value in array element scores[3] to the screen
What loop would work best for the following situation: Exam scores are read from an input file until a negative exam score is encountered. The average of the exam scores is printed to a file.
sentinel - value while (read) loop
What loop would work best for the following situation: The user is prompted to enter the item price. When all prices have been entered, the total is calculated, tax is added and a total amount due is printed to the screen.
sentinel - value while (read) loop
What is computer science
study of machines that execute algorithms
How do you sum the values in an array
sum = 0; for (int 1 = 0; i<SIZE;++i) sum += scores[i];
Is it better to use a symbolic constant for an array size or put the actual number
symbolic constant for ease of modification
What are statements
terminated by a semicolon
What is a preprocessor directive
the # include directive causes contents of another file to be inserted into your program
What does a call to void function contain?
the function name the argument list (which may be empty) a semicolon When a function is called from main, the statements in the body of the function are executed. After the function statements have been executed, control returns to the statement following the call to the function.
What does a function prototype contain
the function return type the function name the parameter type list (which may be empty) a semicolon Function prototypes can be placed outside of main, generally after the using namespace statement
What is a variable scope
the part of a program in which the variable is usable
