Exercises

1. In the Standard C library, the function puts( ) prints a char array to the console (so you can say puts("hello")). Write a C program that uses puts( ) but does not include <stdio.h> or otherwise declare the function. Compile this program with your C compiler (Some C++ compilers are not distinct from their C compilers; in this case you may need to discover a command-line flag that forces a C compilation). Now compile it with the C++ compiler and note the difference.
2. Create a struct declaration with a single member function; then create a definition for that member function. Create an object of your new data type, and call the member function.
3. Change your solution to the previous exercise so the struct is declared in a properly “guarded” header file, the definition is in one cpp file and your main( ) is in another.
4. Create a struct with a single int data member, and two global functions, each of which takes a pointer to that struct. The first function has a second int argument and sets the struct’s int to the argument value, the second displays the int from the struct. Test the functions.
5. Repeat the previous exercise but move the functions so they are member functions of the struct, and test again.
6. Write and compile a piece of code that performs data member selection and a function call using the this keyword (which refers to the address of the current object).
7. Make a Stash that holds doubles. Fill it with 25 double values, then print them out to the console.
8. Repeat the previous exercise with Stack.
9. Create a file containing a function f( ) which takes an int argument and prints it to the console using the printf( ) function in <stdio.h> by saying: printf(“%d\n”, i) where i is the int you wish to print. Create a separate file containing main( ) , and in this file declare f( ) to take a float argument. Call f( ) from inside main( ) . Try to compile and link your program with the C++ compiler and see what happens. Now compile and link the program using the C compiler, and see what happens when it runs. Explain the behavior.
10. Find out how to produce assembly language from your C and C++ compilers. Write a function in C, and a struct with a single member function in C++, and produce assembly language from each and find the function names that are produced by your C function and your C++ member function, so you can see what sort of name decoration occurs inside the compiler.
11. Write a program with conditionally-compiled code in main( ), so that when a preprocessor value is defined one message is printed, but when it is not defined another message is printed. Compile this code experimenting with a #define within the program, then discover the way your compiler takes preprocessor definitions on the command line and experiment with that.
12. Write a program that uses assert( ) with an argument that is always true (nonzero) to see what happens when you run it. Now compile it with #define NDEBUG and run it again to see the difference.
13. Create an abstract data type that represents a video tape in a video rental store. Try to consider all the data and operations that may be necessary for the Video type to work well within the video rental management system. Include a print( ) member function that displays information about the Video.
14. Create a Stack object to hold the Video objects from the previous exercise. Create several Video objects, store them in the Stack, then display them using Video::print( ) .
15. Write a program that prints out all the sizes for the fundamental data types on your computer, using sizeof( ) .
16. Modify Stash to use a vector<char> as its underlying data structure.
17. Dynamically create pieces of storage of the following types, using new: int, long, an array of 100 chars, an array of 100 floats. Print the addresses of these and then free the storage using delete.
18. Write a function that takes a char* argument. Using new, dynamically allocate an array of char which is the size of the char array that’s passed to the function. Using array indexing, copy the characters from the argument to the dynamically allocated array (don’t forget the null terminator) and return the pointer to the copy. In your main( ) , test the function by passing a static quoted character array, then take the result of that and pass it back into the function. Print both strings and both pointers so you can see they are different storage. Using delete, clean up all the dynamic storage.
19. Show an example of a structure declared within another structure (a nested structure ). Declare data members in both structs, and declare and define member functions in both structs. Write a main( ) that tests your new types.
20. How big is a structure? Write a piece of code that prints the size of various structures. Create structures that have data members only and ones that have data members and function members. Then create a structure that has no members at all. Print out the sizes of all these. Explain the reason for the result of the structure with no data members at all.
21. C++ automatically creates the equivalent of a typedef for structs, as you’ve seen in this chapter. It also does this for enumerations and unions. Write a small program that demonstrates this.