CS 180 Exam One Terms and Concepts

Chapter 1

• hardware components: main memory, secondary memory, central processing unit (CPU)
• main memory: random-access memory (RAM), address
• kinds of values stored in memory: integers, real numbers (floats), characters (using ASCII/Unicode), strings, program instructions
• secondary memory: hard disk, floppy disk, CD, flash drive
• programming languages: machine language, assembly language, high-level languages, syntax vs. semantics

Chapter 2

• Components of a program (for now): explanatory comment, preprocessor includes, namespace statement, main function
• use of the cout statement, including << and endl
• variables: programmer-defined named storage locations in memory
  • must be declared
  • must have a type
  • must have a name that follows valid identifier rules
  • may be inititalized with a value at declaration time
• data types: A data type is a set of values and a set of operations defined on those values. Data types so far include:
  • integer: meaning short, int, long, long long, possibly unsigned
    • know which of these is appropriate for various kinds of data
    • know about hex (base 16) and octal (base 8) including literals
  • char: character data type for single characters using single quotes for literals
  • string: old-fashioned C-strings that we will use for string literals and the string Class that we will use later for variables
  • floating-point: meaning float, double, long double
    • literals can use scientific notation 1.4959E11 for example
    • typically always use double
  • bool: meaning a Boolean type, either true or false
• operations:
  • assignment:uses the = sign
    • distinguish left-hand side (lhs, resolves to lvalue aka address) from right-hand side (rhs, resolves to rvalue aka a value)
    • scope: is the regions of the program in which the variable exists and its name can be legally used
    • one form is initialization, can only be done once per variable
    • declaration should be close to where the variable is first used
  • unary minus negates a numeric value
  • addition subtraction multiplication: + - * work the way you would expect
  • division modulus: division is straightforward for floats and works like on your calculator
    • with integer types, does integer division
    • division gives you the quotient
    • modulus gives you the integer remainder
    • modulus can distinguish even from odd, pick out digits, etc. . .
  • parentheses work as you would expect and are useful

Chapter 3

• cin reads data from standard input and converts it to the type of the variable.
• Mathematical operators use precedence and associativity the way you learned in your algebra class.
• Many more mathematical operations are available from the <cmath> library, including pow
• Overflow and underflow can result from arithmetic operations. Mostly they just wrap around without causing errors.
• Mixed type arithmetic operations are possible, but discouraged. Use type casting instead: static_cast<double>(a) casts integer a to a double
• Combined assignment: x += 1; y *= 5;
• Formatting Output: setw(x), fixed, setprecision(x), showpoint