What you learned in week 2:

• Text (strings of letters and symbols) are generally stored in the computer in ASCII code. Each symbol takes one byte.
• Your source code files:
  • If you don't use the line "using namespace std;", then you must precede each standard identifier with std::, as in std::cout, std::endl, etc.
  • What happens if you make various errors in your source code - what the error messages from the compiler look like
  • You can use the program "indent" to re-format your source code
  • Give files short but descriptive names
• Input and output:
  • You can string together multiple outputs into one line, as in cout << "Here's a number: " << variable_1 << endl;
  • You can do calculations in the middle of a cout statement. For example: cout << "The quotient is " << num1/num2;
  • In an output statement, variables are displayed in the proper format, given the type of variable.
  • You can input data from the user and store it into a variable using a "cin" statement.
  • You can input several values with one cin statement - the user must separate the inputs with spaces or enters
  • When you store data into a variable using cin, the data is automatically stored in the proper format, given the type you declared the variable to be. Strings are stored in ASCII, integers in binary, etc.
• Variables:
  • The declaration of a variable declares the type of a variable, reserves space in memory for that variable, and assigns it a name (an identifier) to use throughout the program
  • A variable declaration looks like:
    type variable_name;
  • You can declare two variables on the same line (separate them with commas) provided they are of the same type.
  • There are many different types of built-in and pre-defined types. These include int, float, char, long, bool and string. You learned when to use each of these.
  • The type "string" is used for storing text in a variable. To have a variable of this type, you need to #include <string>
  • Later, we'll learn more about pointer variables. These are for storing memory locations. Here are some example declarations:
    int *integer_location;
float *num_ptr;
  • When you declare a variable, you must choose the appropriate type
  • When you declare a variable, you should choose a short but descriptive name
  • Identifiers (names of variables) can contain letters, digits, or underscores. They may not begin with a digit. They may begin with an underscore but this is strongly discouraged. The case of the letters matters (The name Num is different from num). You may not use reserved words for variable names (Examples of reserved words include int, char, bool, using, main, etc.)
• Arithmetic
  • If you divide two integers, the result is an integer (the remainder is truncated). If you divide two floats, or an integer and a float, the result is a float.
  • The order of precedence for arithmetic operations follows the familiar rules of arithmetic.
• Assignment (the = sign)
  • The assignment operator calculates the expression on the right hand side of the equal sign, then stores it in the variable on the left hand side.
  • The left hand side can't contain arithmetic - it has to be a variable.