CMSC 202 — Spring 2016 — Prof. Marron

Midterm 1 Review Guide

General Concepts

• Compiled vs. interpreted languages (e.g., C++ vs. Python)
• Compiling and Linking
• Invoking the C++ compiler

Basic Syntax

• Legal identifiers
• Allowable characters, case sensitivity
• Rules vs. conventions
• Literals
• Numerical literals (e.g., 1, -5.5)
• String literals (e.g., "Hello, world\n")
• Character literals (e.g., 'A')
• Constants
• Defining using "#define PI 3.14"
• Defining using "const double PI=3.14;"
• Variable Declaration
• Basic format
• Where it can appear
• What "scope" is
• Local variables vs. global variables
• Declaring (or re-declaring) variables in a nested block: nested scope
• Are local variables automatically initialized?
• Basic types in C++
• int, float, double, char, bool
• What is difference between short, int, and long? float and double?
• Operators:
• Arithmetic
• Relational
• Logical (boolean)
• Assignment
• Binary vs. unary operators
• Ternary operator (, e.g. "x == y ? equals++ : equals-- ;")
• Shorthand operators: x++, x--, x += y, x*= y, etc.
• Precedence and associativity
• Expressions, statements
• Type conversion
• In arithmetic operators: e.g. int + double
• in assignment: int x = 5.5;
• Using casts (e.g. "(double) x" or "static_cast<double>x"
• Single statements vs. statement blocks (a.k.a. compound statements)
• Using curly braces: "{...}"
• Comments: "/*...*/", and "//"
• Pitfalls:
• "=" vs. "=="
• forgetting {} with conditional or loop
• loop and array bounds

Console input/output

• cin, cout, cerr
• #include <iostream>
• <<, >> operators

Control Flow

• Conditionals
• Syntax of "if/then/else" statements
• Interpretation of ints as true/false (e.g., is -1 "true"?)
• What does "int x - true" do? What about "bool b = (2 > 1)"?
• Switch statements (essentially a fancy type of conditional)
• Loops
• while(x) { ... }
• do { ... } while (x);
• "for" loops
• break, continue

Minimal Program:

• Should be able to write a simple "Hello, world" program from scratch

The C++ Preprocessor

• #define — what this directive does
• #ifdef/#ifndef/#endif — what these directives do and how they are used to "guard" a header (.h) file

Program file structure:

• Difference between .h and .cpp files
• What to put in each
• How header file includes work:
• #include -- what this directive does
• Why do we "guard" header files?

Functions

• Syntax for declaring a function (a.k.a. "function prototype")
• Syntax for defining a function
• Syntax for calling a function
• Declaring return type
• Declaring formal parameters
• Difference between parameters and arguments
• You should be able to write a simple function from scratch

Function Parameters

• Parameters vs. arguments
• Call-by-value vs. call-by-reference
• Syntax for each
• Difference between the two
• What happens in each case when you reassign a value to a parameter inside the function?
• You should be able to write a simple swap() function that exchanges the actualy parameter variables so that caller is affected.
• "const" parameters: (e.g. "void Foo(const int x) { ... }"
• What does declaring a parameter to e "const" do?

Arrays

• How to declare local variable as an array
• Initializing arrays
• How are C-strings represented? Array-of-chars...
• How are arrays stored?
• Accessing array elements: using "x[pos]" indexing
• How to declare as parameter in function declaration/definition
• Are array arguments to function calls passed by-value or by-reference?

Basic Pointers:

• How to declare a pointer (e.g. "int *xPtr" to declare xPtr as "pointer to int")
• How to get the address of another variable (e.g. "xPtr = &myInt")
• Using pointers to simulate call-by-reference
• Pointer arithmetic: what would "*(xPtr + 1) = 0" do?
• "*" (dereference) and "&" (address of) operators
• Use of new, delete, and delete []

Structures

• What are they?
• How to define one
• How to use one

Basic Classes

• What is a class?
• Difference from a struct
• Class "interfaces"
• Encapsulation / Abstract Date Type
• What is benefit of keeping implementation details from user?
• Syntax for defining a class
• Data members and function members
• private versus public members
• Accessors, mutators, facilitators
• Where/how to define member functions
• Constructors:
• What is the purpose of a constructor?
• Default vs. non-default constructors
• Initialization lists for constructors
• Aggregation:
• Including classes (actually, class isntances) inside other classes
• Why would you do this?

Makefiles

• What are targets, dependencies, and recipes?
• Why do we separate compilation and linking?
• Be able to complete a simple makefile.