17.  a, d
18.
void func(char*);
19.
for(int j=0; j<80; j++)
*s2++ = *s1++;
20.  b
21.
char* revstr(char*);
22.
char* numptrs[] = { “One”, “Two”, “Three” };
23.  a, c
24.  wasted
25.  memory that is no longer needed
26.
p->exclu();
27.
objarr[7].exclu();
28.  a, c
29.
float* arr[8];
30.  b
31.  0..9 at one end; 3..* at the other
32.  b
33.  false
34.  a
Solutions to Exercises
1.
// ex10_1.cpp
// finds average of numbers typed by user
#include <iostream>
using namespace std;
int main()
{
float flarr[100];                   //array for numbers
char ch;                            //user decision
int num = 0;                        //counts numbers input
do
{
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cout << “Enter number: “;        //get numbers from user
cin >> *(flarr+num++);           //until user answers ‘n’
cout << “   Enter another (y/n)? “;
cin >> ch;
}
while(ch != ‘n’);
float total = 0.0;                  //total starts at 0
for(int k=0; k<num; k++)            //add numbers to total
total += *(flarr+k);
float average = total / num;        //find and display average
cout << “Average is “ << average << endl;
return 0;
}
2.
// ex10_2.cpp
// member function converts String objects to upper case
#include <iostream>
#include <cstring>       //for strcpy(), etc
#include <cctype>        //for toupper()
using namespace std;
////////////////////////////////////////////////////////////////
class String             //user-defined string type
{
private:
char* str;                    //pointer to string
public:
String(char* s)               //constructor, one arg
{
int length = strlen(s);    //length of string argument
str = new char[length+1];  //get memory
strcpy(str, s);            //copy argument to it
}
~String()                     //destructor
{ delete str; }
void display()                //display the String
{ cout << str; }
void upit();                  //uppercase the String
};
//--------------------------------------------------------------
void String::upit()                 //uppercase each character
{
char* ptrch = str;               //pointer to this string
while( *ptrch )                  //until null,
{
*ptrch = toupper(*ptrch);     //uppercase each character
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ptrch++;                      //move to next character
}
}
////////////////////////////////////////////////////////////////
int main()
{
String s1 = “He who laughs last laughs best.”;
cout << “\ns1=”;       //display string
s1.display();
s1.upit();             //uppercase string
cout << “\ns1=”;       //display string
s1.display();
cout << endl;
return 0;
}
3.
// ex10_3.cpp
// sort an array of pointers to strings
#include <iostream>
#include <cstring>              //for strcmp(), etc.
using namespace std;
const int DAYS = 7;             //number of pointers in array
int main()
{
void bsort(char**, int);     //prototype
//array of pointers to char
char* arrptrs[DAYS] = { “Sunday”, “Monday”, “Tuesday”,
“Wednesday”, “Thursday”,
“Friday”, “Saturday”  };
cout << “\nUnsorted:\n”;
for(int j=0; j<DAYS; j++)    //display unsorted strings
cout << *(arrptrs+j) << endl;
bsort(arrptrs, DAYS);        //sort the strings
cout << “\nSorted:\n”;
for(j=0; j<DAYS; j++)        //display sorted strings
cout << *(arrptrs+j) << endl;
return 0;
}
//--------------------------------------------------------------
void bsort(char** pp, int n)    //sort pointers to strings
{
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void order(char**, char**);  //prototype
int j, k;                    //indexes to array
for(j=0; j<n-1; j++)         //outer loop
for(k=j+1; k<n; k++)      //inner loop starts at outer
order(pp+j, pp+k);           //order the pointer contents
}
//--------------------------------------------------------------
void order(char** pp1, char** pp2)  //orders two pointers
{                            //if string in 1st is
if( strcmp(*pp1, *pp2) > 0)  //larger than in 2nd,
{
char* tempptr = *pp1;     //swap the pointers
*pp1 = *pp2;
*pp2 = tempptr;
}
}
4.
// ex10_4.cpp
// linked list includes destructor
#include <iostream>
using namespace std;
////////////////////////////////////////////////////////////////
struct link                           //one element of list
{
int data;                          //data item
link* next;                        //pointer to next link
};
////////////////////////////////////////////////////////////////
class linklist                        //a list of links
{
private:
link* first;                    //pointer to first link
public:
linklist()                      //no-argument constructor
{ first = NULL; }            //no first link
~linklist();                    //destructor
void additem(int d);            //add data item (one link)
void display();                 //display all links
};
//--------------------------------------------------------------
void linklist::additem(int d)         //add data item
{
link* newlink = new link;          //make a new link
newlink->data = d;                 //give it data
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newlink->next = first;             //it points to next link
first = newlink;                   //now first points to this
}
//--------------------------------------------------------------
void linklist::display()              //display all links
{
link* current = first;             //set ptr to first link
while( current != NULL )           //quit on last link
{
cout << endl << current->data;  //print data
current = current->next;        //move to next link
}
}
//--------------------------------------------------------------
linklist::~linklist()                 //destructor
{
link* current = first;             //set ptr to first link
while( current != NULL )           //quit on last link
{
link* temp = current;           //save ptr to this link
current = current->next;        //get ptr to next link
delete temp;                    //delete this link
}
}
////////////////////////////////////////////////////////////////
int main()
{
linklist li;       //make linked list
li.additem(25);    //add four items to list
li.additem(36);
li.additem(49);
li.additem(64);
li.display();      //display entire list
cout << endl;
return 0;
}