Spring 2000 Midterm Review

Topics

• pass-by-value/pass-by-reference
• Definition
• What is the difference between the two?
• When do you use pass-by-value?
• When do you use pass-by-reference?
• How do you implement pass-by-reference using pointers?
• pointers
• Definition
• Using pointers
• Pointer arithmetic
• Addition
• Subtraction
• Use of operators( +, ++, +=, -, --, -=)
• Use of dereference operator (*)
• Use of "address of" operator (&)
• Relation to arrays
• How is pointer like an array?
• How is pointer different?
• Using pointers to access array
• dynamic memory allocation
• Definition
• Why do we need dynamic memory allocation?
• using the new and delete operators
• to allocate a single variable
• to allocate an array
• to delte a variable
• to delete an array (using delete [])
• What is a memory leak?
• Why is it bad?
• strings
• What is a string?
• How are strings represented in memory?
• String functions
• strlen()
• strcpy()
• strncpy()
• strcmp()
• strncmp()
• strcat()
• strncat()
• strstr()
• Difference between the simple string functions and the 'n' versions of the functions.
• Why is it better to use the 'n' version of the function?
• recursion
• Definition
• Recursion vs Iterative solutions
• What is the difference between the two?
• Can you solve all recursive problems iteratively?
• Is the reverse true?
• classes
• Abstract data type
• Definition
• What is a class?
• Declaring a class
• Declaring functions for a class
• Constructors/Destructors
• What are they?
• How to declare them
• Why are they useful
• When do you need a destructor?
• Protection
• What kind of protection/information hiding mechanisms do classes provide?<\li>
• What do private: and public: do?
• Why do we want to be able to control access to members of a class?
• Why are classes useful?
• Function Overloading
• What is it?
• How do you do it?
• How is it useful?
• Types
• What is a type
• What kinds of things can be used as types? (classes, structs, etc...)

Samples of things that might be asked

Definitions

Short answer and/or true or false based on the definitions of all the stuff up there in the topics list for which I said you need to know the definition for. If you don't know the definition for some of the topics, then ask.

Understanding of types

Given the following code:

class myclass
{
public:
       int     thingy;
       double *gadget;
       char myword[20];
};

myclass var1;
char *var2;
myclass var3[10];

What are the types of the following expressions?

1. var3[2]	A. int
2. thingy	B. double
3. var1.myword	C. character
4. var3	D. calss
5. *var2	E. double pointer
6. myclass	F. integer pointer
7. *(var1.gadget)	G. Character pointer
8. var3.gadget	H. string
9. var1.myword+1	I. myclass
10. var3[2].myword[2]	J. invalid
	K. none of the above

Answers:
1. I
2. J
3. G or H
4. K
5. C
6. J
7. B
8. J
9. G or H
10. C

Understanding of pointers/arrays

Show the value of each position in the array A after the following code has been performed.

    int A[5]={10,2,1,8,4};
    int *ip;
    ip=A;
    *ip=12;
    ip++;
    *ip+=4;
    *(ip+2)+= *ip;
    ip+=3;
    (*ip)++;
    *(ip-2)= *(ip-1)+2;

Answer:
[12,6,16,14,5];

Understanding of recursion

You will be asked to write a short recursive function similar to the recursive functions you did on the first assignment or the one's we covered in class.

Understangind of Classes

You will be asked to write a small class very similar to the class you had to write for Lab 3

Understanding of Strings

You will be asked to write a short function that requires you to used some of the string functions listed above.

This is the tentatibe format for the midterm. Things might change slightly here or there but if you know the above topics well you should do fine on the test. If you have any questions send email to the CS12 mailing list good luck!