Chapter 2Computer data processingData typesData types continuedSlide 5How is main memory (RAM) organized and accessedSize of storage or memory needed to store a piece of dataArithmetic operatorsArithmetic operators continuedInteger divisionMixed mode operation and data type promotionOutput using coutThe insertion operator << is “overloaded”Formatted outputCommonly used stream manipulatorsExample: Version 1; printout not properly alignedExample: Version 2; printout of integers is now properly aligned with setw(n)Formatting floating point numbersMore examples on the effect of format manipulators are shown in table 2-8, page 52Format flags for use with setiosflags( ) on page53A program that illustrates output conversionsA simpler versionVariable and its declarationVariable nameDeclaration of variablesSlide 26The assignment operator =Example: compute the average of three test scoresExample: character variableReference variable: additional name or alias of the same variableProgram involving reference variableChapter 2 Data types, declarations, and displaysComputer data processing•Data processing: the process of using a computer to convert raw data (unprocessed or unorganized) data into information (processed data).Data types•Numeric (dimensionless)–integer type: 450, 25000, -99, etc.–floating point type•Ordinary notation: 3.1415, 6.99, -12000., etc.•Exponential notation: for very large or very small values such as 6.25e9, -3.5e-10, etc.–Character type: a single character enclosed in a pair of single quote such as ‘a’, ‘Z’, ‘$’, etc. In C/C++ system, a character is internally treated/represented as an small integer, e.g., ‘a’ is actually 97 ‘A’ is 65.Data types continued–Character type: although C/C++ treats a single character as an integer, each character is encoded using a group of eight bits following a coding standard known as ASCII (American Standard for Information Interchange) of ANSI (American National Standard Institute). For example, when you hit ‘a’ key, a group of eight bits 01100001 goes into the memory (see p38).–Boolean or logical type: recent C/C++ standard supports Boolean type. A Boolean data type allows only two different values of either true or false. Again, Boolean values are treated by C/C++ as two small integer values --- 1 for true and 0 for false.Data types continued–Character type: there are a small set of characters known as escape sequence (or escape characters) including ‘\n’ (a new line character), ‘\t’ (next tab stop character), etc. (see Tab 2-3 on p39). Although there are two characters enclosed in a pair of single quotes, the two characters are treated as a single character or more precisely, a small integer, ‘\n’ is 10 and ‘\t’ is 9. Note that escape character such as ‘\n’ and ‘\t’ play important role in output operation.–String type: a series or a list of characters enclosed in a pair of double quotes such as “William Paterson Univ”, “Net Income”, etc.How is main memory (RAM) organized and accessed•RAM is byte-addressable (each byte has a unique address) with a one-dimension or linear memory space, i.e., one byte after another.•How many bytes are needed to store an integer, a floating point number, a character, or a string?Size of storage or memory needed to store a piece of data–Integer type•short: 2 types •int: 2 types •long: 4 types –Floating•float: 4 bytes •double: 8 bytes •long double: 10 bytesIt is noted that the larger the size of storage, the wider the range and more precise can a value be stored. Also noted is the fact that the sizes are dependent on the compiler! The numbers quoted are for Turbo C/C++ compiler.Arithmetic operators•+ (addition), - (subtraction), * (multiplication), / (division), % (modulo division). Note that except for modulo division operator which operate on integers, all other four operator operate on either integer or floating point types of data.•Property of an operator–arity: number of operands operated upon by the operator.–priority or precedence: the order of operations when two or more operators appear in a statement or expression.–associativity: either left-to-right or right-to-left.Arithmetic operators continued•All operators are binary operators (with arity = 2) since each operates on two operand such as 4 * 5, 8 – 6, etc.•the – operator can be a unary negation operator (one operand) as in –25, where – simply mean negative 25.•The associativity is left-to-right meaning 5 - 3 is actually 5 minus 3, not 3 minus 5.•*, /, and % are of the same priority and are higher than + and -, meaning 2 + 3 * 5 is equal to 17 instead of 25! Note that precedence can be overridden with parentheses.Integer division•5 / 3 yields 1 (quotient)•99 / 100 yields 0 (quotient)•5 % 3 yields 2 (remainder)•99 % 100 yields 99 (remainder)•etc.Mixed mode operation and data type promotion•In an arithmetic expression, there are two or more operands of different types (a mix of integer and floating point types)Example: 2 + 3.5 (2 will be promoted to double type before computation will take place)4.85 – 3.1415926L (4.85 will be promoted to long double type before computation will proceed) etc.Output using cout•Data flows like a stream (one character after another) to or out of a C++ program.•cout is an ostream (output stream) object (it is helpful to view it as an output stream); it is used together with the insertion operator <<, which inserts whatever follows it to the output stream.Example:cout << “Hello World!” << endl;cout << (2 + 3) << endl;cout << “The first alphabet is “ << ‘a’ << endl;cout << “The total of 6 and 15 is “ << (6 + 15); etc…The insertion operator << is “overloaded”•Notice the insertion operation recognizes and inserts (or operates on) different types data item onto the output stream (which flows from the program to a printer or monitor); the insertion operator is said to be overloaded.Formatted output•For simple formatting, one can use escape sequence such as ‘\n’ (newline) and/or ‘\t’ (next tap stop).•For more sophisticated formatting, one must use stream manipulators which are defined by the C/C++ system.Commonly used stream manipulators•setw( n ): set field width to n•setprecision( n ): set floating point precisin to n places•setiosflag( flags ): set the format flags•dec: display a value in decimal notation•hex: display a value in