Final Review

Ying Wu Electrical Engineering & Computer

ScienceNorthwestern Universityyingwu@ece.northwestern.edu

EECS 230 Lectures Series

About EECS 230 The goal

– Getting a good glimpse of C/C++ programming– Learning a real useful programming language– Understanding software design– Accumulating experience– Becoming a junior programmer

What I want to concentrate– Familiarizing C/C++ syntax– Understanding important and core C/C++ concepts– Grasping a tool, i.e., the Debugger– Finding the best way for further study

What are beyond– Data structure– Compiler and OS– Algorithms– Architecture

Grading Scale

MPs and exams[MPs Midterm Final][30% 30% 40%]

The weights for MPs[MP#1, MP#2, MP#3, MP#4, MP#5, MP#6, MP#7,

MP#8][ 3% 3% 3% 5% 4% 4% 4%

4% ]

Grade scale A/A- > 40%B+/B/B- > 45%C+/C/C- < 15%D you can figure it out!

CTEC survey

Please fill the CTEC survey Our course number: EECS 230-0-20 Instructor:

– Professor Ying Wu TAs are:

– Ming Yang – David Choffnes – Yao Zhao

What we’ve learned (I)

Basic C/C++ syntax– Data type– Control

if, if/else, switch, while, do/while, for

– Pointer, array, reference– Function– C++ Class

What we’ve learned (II) Basic C/C++ concepts

– FunctionCall-by-value vs. call-by-reference What can be returned and what can not be

return?

– Array and pointers Relationship? (similarity and dissimilarity)Data in memory

– Local variable and scope (life-cycle)– Pointers and references

What is reference? Why is it special?Point arithmetic

– static– Const

What We’ve learned (III) Advanced C++ concepts

– Dynamic Memory Allocation – Classes with pointer data members – Copy constructor – Operator overloading– Constructors/destructors

When constructors and destructors are called

– Linked list

About Final exam

Date: March 16th (Fri) 9 – 11 am Place: Tech LR4 Content:

– Several straightforward problems– Read code and write results– Write code

For your benefits– Be extremely careful– Write down your intermediate results

(as more as you can) for partial credits

Let’s Warm up …Questions 1:

int a = 2, b = 4, c;

c = (++a >= 3 ? b -- : b ++);

Then a = ? b = ? c = ?

Questions 2:

int a = 2, b = 0, c = 0;

While ( a < 4){

b += c ++;

a ++;

}

Then a = ? b = ? c = ?

2D pointers Important Concepts

int *p1;– p1 is a pointer– What does p1 point to?

Can be an integerCan be an integer array and we can index by p1[n]. Here p1[n] is an integer

int **p2;– p2 is a pointer– What does p2 point to?

Can be a pointer pointing to an integerCan be an array of pointers and we can index by p2[n]. Here p2[n] is a pointer! Therefore, p2[n] can point to an integer or an integer array.

810010000

1001000010020008

1002000810090080

int a = 8;

int *pa = &a;

int **ppa = &pa;

Question:

[1] (*pa) = ?

[2] (**ppa) = ?

10010000

1001000010020008

int *pa = new int [3];

10014006

10020008

int **ppa = new int* [3];

for(int k=0;k<3;k++)

ppa[k] = new int [3];

1002000810090080

10010308

10010000

10010000

10010308

10014006 Question:

(1) ppa[1] = ?

(2) ppa[1][2] = ?

(3) ppa + 2 = ?

Example: Table

I want to implement a general table class, which holds any size of row/column.

How can I construct such a table? What should we do for the constructor and

destructor?

class CTable()

{

int **m_pData;

int m_nRow;

int m_nCol;

public:

CTable(int r = 1, int c = 1);

~CTable();

…

};

CTable::CTable(int r, int c)

{

assert(r>0 && c>0);

m_nRow = r;

m_nCol = c;

m_pData = new int *[m_nRow];

assert(m_pData != NULL);

for(int k=0; k<m_nRow; k++){

m_pData[k] = new int [m_nCol];

assert(m_pData[k] != NULL);

}

}

CTable::~CTable()

{

for(int k=0; k<m_nRow; k++)

delete [] m_nData[k];

delete [] m_nData;

}

Local variable and scopeint myfunc(int a, int& b)

{

int c;

c = a + b;

return c;

}

Questions:• What are the exact stuff passed to the function?

• What happen to the memory when executing into the function?• What are the exact stuff return from the function?

• What can NOT be returned?

• What if a/b/c/t1/t2/t are not just int but objects?

void main()

{

int t, t1 = 1, t2 = 1;

t = myfunc(t1 + t2);

}

copy

t

t1=1

t2=1

a

c

c’

copy

An interesting questionint *LocationOfAge()

{

int age;

cin >> age;

// missing code here

}

return &age;

int *p = new int;

*p = age;

return p;

return (new int(age));

When constr/desctr are calledclass M

{

public:

M();

M(const M & );

~M();

};

M::M()

{

cout << "call default constructor\n";

}

M::M(const M & m)

{

cout << "call copy constructor\n";

}

M::~M()

{

cout << "call destructor\n";

}

void myfun1(M t)

{

cout << "go inside myfunc1()\n";

}

M& myfun4()

{

cout << “go inside myfunc4()\n”;

M *temp = new M;

return *temp;

}

void myfun2(M &t)

{

cout << "go inside myfunc2()\n";

}

M myfun3()

{

cout << “go inside myfunc3()\n”;

M temp;

return temp;

}

void myfun1(M t);

void myfun2(M &t);

M myfun3();

M& myfun4();

void main()

{

M a;

M b = a;

M c(a);

myfun1(b);

myfun2(a);

a = myfun3();

b = myfun4();

M *d = new M;

delete d;

}

call default constructor

call copy constructor

call copy constructor

call copy constructor

go inside myfunc1()

call destructor

go inside myfunc2()

go inside myfunc3()

call default constructor

call copy constructor

call destructor

call destructor

go inside myfunc4()

call default constructor

call default constructor

call destructor

call destructor

call destructor

call destructor

IMPORTANT!

RUN this example by yourself!

Linked list

class CNode {

public:

CNode( const int &d ) : data(d), nextPtr(0){};

 

int data;

CNode *nextPtr;

};

Linked list

Question: how do you find 8 in the list?

firstPtr

7 9 8 35

Node* find(Node* firstPtr, int q)

{

ListNode *curPtr = firstPtr; // step I

while (curPtr != NULL) // step II

if (curPtr->data == q) // step III

break;

curPtr = curPtr->nextPtr; // step IV

}

return curPtr;

}

Question: how to allocate a node to hold 10?

Question: how to insert the node of 10 after 8? (8 could be the last one in the list)