CS102 Midterm Exam (1)

Midterm Exam (1)
C++ Programming
NCNU CSIE

Date: February 23rd, 2011
Time: 14:10-16:00
Open book; turn off computer & mobile phone

(10%) Determine whether the following code has syntax erros or not. If it is correct, predict its output. If it is incorrect, point out the mistake(s).

#include <iostream>
using std::cout;
using std::endl;

void test(char p[])
{  cout << ++p << endl;
}

int main()
{
    char *name = "ABCD";
    test(name++);
    cout << ++name << endl;
}

(10%) Determine whether the following code has syntax erros or not. If it is correct, predict its output. If it is incorrect, point out the mistake(s).

// Pass-by-reference
#include <iostream>
using std::cout;
using std::endl;

void print(int i, int j)
{
    cout << "i = " << i << "\t j = " << j << endl;
}

void swap1(int a, int b)
{   int temp;
    temp = a; a = b; b = temp;
}
void swap2(int &a, int &b)
{   int temp;
    temp = a; a = b; b = temp;
}
void swap3(int &a, int b)
{   int temp;
    temp = a; a = b; b = temp;
}

int main()
{
    int i=20, j=11;
    swap1(i,j); print(i,j);
    swap2(i,j); print(i,j);
    swap3(i,j); print(i,j);
}

(10%) What will be the output of the following program?

#include <iostream>
using std::cout;
using std::endl;

struct Node
{
  char value;
  Node* left;
  Node* right;
};

void print(Node* r)
{
	if (r->left != NULL) print(r->left);
	cout << r->value;
	if (r->right != NULL) print(r->right);
	return;
}

int main(void)
{
	Node a = { 'A', 0, 0 };
	Node b = { 'B', 0, 0 };
	Node h = { 'H', &a, &b };
	Node c = { 'C', 0, 0 };
	Node d = { 'D', 0, 0 };
	Node g = { 'G', &c, &d };
	Node i = { 'I', &h, &g };
	Node f = { 'F', 0, 0 };
	Node e = { 'E', &i, &f };
	print(&e);
	cout << endl;
  return 0;
}

(10%) Determine whether the following code has syntax erros or not. If it is correct, predict its output. If it is incorrect, point out the mistake(s).

#include <iostream>
using std::cout;
using std::endl;

struct Node
{
  char value;
  Node* left;
  Node* right;
};

void print(Node* r)
{
	if (r->left != NULL) print(r->left);	
	if (r->right != NULL) print(r->right);
	cout << r->value;
	return;
}

int main(void)
{
	Node a = { 'A', 0, 0 };
	Node b = { 'B', 0, 0 };
	Node h = { 'H', &a, &b };
	Node c = { 'C', 0, 0 };
	Node d = { 'D', 0, 0 };
	Node g = { 'G', &c, &d };
	Node i = { 'I', &h, &g };
	Node f = { 'F', 0, 0 };
	Node e = { 'E', &i, &f };
	print(&i);
	cout << endl;
  return 0;
}

(10%) Determine whether the following code has syntax erros or not. If it is correct, predict its output. If it is incorrect, point out the mistake(s).

// Importance of the "break" statement in the "switch" statement
#include <iostream>
using std::cout;
using std::endl;

int main(void)
{
	char str[] = "TAIWAN";
	char *p = str;
	int vowel = 0;
	int consonant = 0;
	for ( ; *p != '\0'; p++)
		switch (*p) 
		{
			case 'A':
			case 'E':
			case 'I':
			case 'O':
			case 'U':
				vowel++;
			default:
				consonant++;
		}
	cout << vowel << '\t' << consonant << endl;
  return 0;
}

(10%) Determine whether the following code has syntax erros or not. If it is correct, predict its output. If it is incorrect, point out the mistake(s).

// Matrix Multiplication
#include <iostream>
using std::cout;
using std::endl;

int main(void)
{
    int A[][5] = {    { 0, 0, 0, 0, 1},
                    { 0, 0, 0, 1, 0 },
                    { 0, 0, 1, 0, 0 },
                    { 0, 1, 0, 0, 0 },
                    { 1, 0, 0, 0, 0 } };
    int B[5][5] = { 0 };
    int i, j, k;
    for (i=0; i<5; i++)
        for (j=0; j<5; j++)
            for (k=0; k<5; k++)
                B[i][j] += A[i][k] * A[k][j];
    for (i=0; i<5; i++)
    {
        for (j=0; j<5; j++)
            cout << B[i][j];
        cout << endl;
    }
return 0;
}

(10%) Determine whether the following code has syntax erros or not. If it is correct, predict its output. If it is incorrect, point out the mistake(s).

#include <iostream>

using std::cout;
using std::endl;

int main()
{
    char str[10] = "February";
    char* p = str;
    cout << str << endl;
    cout << *(++p) << endl;
    for ( ; *p != '\0'; p++)
        *p ^= 0x20;
    cout << sizeof(*p) << endl;
    cout << str << endl;
}

(10%) Determine whether the following code has syntax erros or not. If it is correct, predict its output. If it is incorrect, point out the mistake(s).

// Manipulator hex
#include <iostream>
using std::cout;
using std::endl;
using std::hex;

int main(void)
{
	int c1 = 'A', c2 = 'a';
	c1 ^= c2;	cout << hex << c1 << c2 << endl;
	c2 ^= c1;	cout << hex << c1 << c2 << endl;
	c1 ^= c2;	cout << hex << c1 << c2 << endl;
	return 0;
}

(10%) Determine whether the following code has syntax erros or not. If it is correct, predict its output. If it is incorrect, point out the mistake(s).

// Linked-List
#include <iostream>
using std::cout;
using std::endl;

struct Node
{
	int value;
	Node* next;
};

Node* insert(Node* head, int n)
{
	Node* p = new Node;
	p->value = n;
	p->next = head;
	return p;
}

void print_list(Node* p)
{
	int n = 0;
	while (p)
	{
		cout << "Line " << ++n << ":" << p->value << endl; 
		p = p->next;
	}
	return;
}

int main(void)
{
	int A[] = { 1, 3, 5, 7, 2, 4, 6 };
	int n = sizeof(A) / sizeof(A[0]);
	Node* head = NULL;
	for (int i=0; i<n; i++)
		head = insert(head, A[i]);
	print_list(head);
	return 0;
}

(10%) Determine whether the following code has syntax erros or not. If it is correct, predict its output. If it is incorrect, point out the mistake(s).

// Structure array
#include <iostream>
using std::cout;

struct POINT
{
    int x;
    int y;
}

int Area(POINT p1, POINT p2)
{ return (p2.x - p1.x) * (p2.y - p1.y);
}

int main()
{
    POINT p[2] = { { 10, 40 } , { 50, 60 } };
    cout << Area(p[0], p[1]) << "\n";
    return 0;
}
(10%) Determine whether the following code has syntax erros or not. If it is correct, predict its output. If it is incorrect, point out the mistake(s).

// Linked-List
#include <iostream>
using std::cout;
using std::endl;

struct Node
{
    int value;
    Node* next;
};

Node* insert(Node* head, int n)
{
    Node* p = new Node;
    p->value = n; p->next = NULL;
    Node* p2 = head;
    Node* p1 = p2;

    if (p2 == NULL)
        return p;

    while (p2->value < p->value && p2->next != NULL)
    {
        p1 = p2;
        p2 = p2->next;
    }

    if (p2->value < p->value)
    {
        p->next = p2->next;
        p2->next = p;
        return head;
    }
    else
        if (p1==p2)        // n is less than the first element
        {
            p->next = p1;
            return p;
        }
        else
        {
            p->next = p2;
            p1->next = p;
            return head;
        }
}

void print_list(Node* p)
{
    int n = 0;
    while (p)
    {
        cout << p->value << endl;
        p = p->next;
    }
    return;
}

int main(void)
{
    int A[] = { 1, 3, 5, 7, 2, 4, 6 };
    int n = sizeof(A) / sizeof(A[0]);
    Node* head = NULL;
    for (int i=0; i<n; i++)
        head = insert(head, A[i]);
    print_list(head);
    return 0;
}

Midterm Exam (1) C++ Programming NCNU CSIE

Midterm Exam (1)
C++ Programming
NCNU CSIE