C++ Summary First Steps:

• Compiler
  • The C++ compiler is invoked by "CC"
  • "CC" will also compile C programs, so you can type
    CC hw.c
    and get an "a.out" as usual.
    CC Word_count.c get_word.c btree.c
    will compile Assignment 6.
• Comments.
  • C++ supports single line comments.
    pp++; // this comment goes to the end of the line
    but does not go over to the next. If you need multi-line comments you can still use the /* ... */ from C.
• Just in time declarations.
  • C++ requires declarations just as C does, but declarations can occur anywhere in the code, not just at the top.
    for( int ii=0; ii < argc; ii++)
    is a perfectly legal C++ for loop provided "argc" has already been declared.
  • The declaration is in effect inside the smallest { . . . } pair containing the declaration.
• Output to the screen.
  • There is a new IO method in C++. You need a line
    #include < iostream.h >
    which is used instead of
    #include < stdio.h >
    
  • Printing of the standard data types.
    • To print "hello world" on a line by itself we now say
      cout << "hello world\n";
      
      • To print the decimal integer contained in the variable "x" on a line by itself, we now say
        cout << x <<"\n";
        
  • Mix and Match.
    • You can use "printf" just as before but it takes a bit of set up. You need to include both
      < iostream.h > and < stdio.h >
      and then call the function
      ios::sync_with_stdio();
      This is the C++ standard but the CC compiler seems to manage without explicitly calling sync_with_stdio.
    • You can also use the C library function "sprintf" from Appendix B. This function does the "prontf" thing but instead of printing the result, it puts it in a C-string. You can then ship the C-string to "cout".
• Function and operator overloading.
  • Functions can be overloaded, which means that different functions can have the same name. For example, in a geometry program we might have rectangles, circles and pentagons. We might want to write functions to compute the areas of an instance of each of these figures. If rect* points to a rectangle, circ* to a circle and pent* to a pentagon then in C++ we can have three functions, all called Area, with three declarations
    double Area(rect*);
    double Area(circ*);
    double Area(pent*);
    
  • With a bit more work, operators can be overloaded as well so we can define a complex number data type and if c1 and c2 are complex numbers, write c1=c1+c2 and have the expected thing happen.

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Math 211 homepage.
C++ Classes.
C++ Overloading.
C++ Derivation.