1.根据这个头文件：
// golf.h -- for pe9-1.cpp const int Len = 40; struct golf { char fullname(Len); int handicap; }; // non-interactive version: // function sets golf structure to provided name, handicap // using values passed as arguments to the function void setgolf(golf & g, const char * name, int hc); // interactive version: // function solicits name and handicap from uaer // and sets the members of g to the valus entered // returns 1 if name is entered, 0 if name is empty string int setgolf(golf & g); // function resets handicap to new value void handicap(golf & g, int hc); // function displays contents of golf structure void showgolf(const golf &g);
注意到setgolf()被重载，可以这样使用其第一个版本：
golf ann; setgolf(ann, "Ann Birdfree", 24);
上述函数调用提供了存储在ann结构中的信息。可以这样使用其第二个版本：
golf andy; setgolf(andy);
上述函数将提示用户输入姓名和等级，并将它们存储在andy结构中。这个函数可以（但是不一定必须）在内部使用第一个版本。
根据这个头文件，创建一个多文件程序。其中的一个文件名为golf.cpp，它提供了与头文件中的原型匹配的函数定义；另一个文件应包含main()，并演示原型化函数的所有特性。例如，包含一个让用户输入的循环，并使用输入的数据来填充一个由golf结构组成的数组，数组被填满或用户将高尔夫选手的姓名设置为空字符串时，循环将结束。main()函数只使用头文件中原型化的函数来访问golf结构。
// golf.h
#include "golf.h"
#include <iostream>
#include <cstring>
using namespace std;
void setgolf(golf & g, const char * name, int hc){
strcpy(g.fullname, name);
g.handicap = hc;
}
int setgolf(golf & g){
cout << "Fullname:";
cin.getline(g.fullname, Len);
if(strlen(g.fullname) == 0){
return 0;
}
cout << "Handicap:";
cin >> g.handicap;
cin.get();
return 1;
}
void handicap(golf & g, int hc){
g.handicap = hc;
}
void showgolf(const golf &g){
cout << "Fullname:" << g.fullname << endl;
cout << "Handicap:" << g.handicap << endl;
}#include "golf.h"
#include <iostream>
const int size = 2;
using namespace std;
int main(){
golf ann;
setgolf(ann, "Ann Birdfree", 24);
showgolf(ann);
golf andy;
if(setgolf(andy) == 1)
showgolf(andy);
else{
setgolf(andy, "Andy Bird", 50);
handicap(andy, 40);
showgolf(andy);
}
golf g[size];
for(int i = 0; i < size; i++){
cout << "#" << i + 1 << ":" << endl;
int flag = setgolf(g[i]);
if(flag == 0){
setgolf(g[i], "kk", 3);
}
}
for(int i = 0; i < size; i++){
cout << "#" << i + 1 << "info:" << endl;
showgolf(g[i]);
}
return 0;
}2.修改程序清单9.9：
//Listing 9.9 static.cpp // static.cpp -- using a static local variable #include <iostream> // constants const int ArSize = 10; // function prototype˜ void strcount(const char *str); int main() { using namespace std; char input[ArSize]; char next; cout << "Enter a line:\n"; cin.get(input, ArSize); while (cin) { cin.get(next); while (next != '\n') // string didn't fit! cin.get(next); // dispose of remainder strcount(input); cout << "Enter next line (empty line to quit):\n"; cin.get(input, ArSize); } cout << "Bye\n"; return 0; } void strcount(const char *str) { using namespace std; static int total = 0; int count = 0; // static local variable // automatic local variable cout << "\"" << str << "\" contains "; while (*str++) // go to end of string count++; total += count; cout << count << " characters\n"; cout << total << " characters total\n"; }
用string对象代替字符数组。这样，该程序将不再需要检查输入的字符串是否过长，同时可以将输入字符串同字符串“”进行比较，以判断是否为空行。
代码如下
//Listing 9.9 static.cpp
// static.cpp -- using a static local variable
#include <iostream>
#include <string>
// constants
//const int ArSize = 10;
// function prototype?
using namespace std;
void strcount(string str);
int main()
{
// char input[ArSize];
string input;
char next;
cout << "Enter a line:\n";
// cin.get(input, ArSize);
getline(cin, input);
while (input.size())
{
// cin.get(next);
// while (next != '\n') // string didn't fit!
// cin.get(next); // dispose of remainder strcount(input);
strcount(input);
cout << "Enter next line (empty line to quit):\n";
getline(cin, input);
}
cout << "Bye\n";
return 0;
}
void strcount(const string str)
{
using namespace std;
static int total = 0;
int count;
// static local variable // automatic local variable
cout << "\"" << str << "\" contains ";
count = str.size();
total += count;
cout << count << " characters\n";
cout << total << " characters total\n";
}3.下面是一个结构声明：
struct chaff { char dross[20]; int slag; };
编写一个程序，使用定位new运算符将一个包含两个这种结构的数组放在一个缓冲区中。然后，给结构的成员赋值（对于char数组，使用函数strcpy()），并使用一个循环来显示内容。一种方法是像程序清单9.10那样将一个静态数组用作缓冲区；另一种方法是使用常规new运算符来分配缓冲。
#include <iostream>
#include <cstring>
using namespace std;
struct chaff
{
char dross[20];
int slag;
};
int main(){
chaff *ch = new chaff[2];
strcpy(ch[0].dross, "aabbccddee");
ch[0].slag = 12;
strcpy(ch[1].dross, "abcde");
ch[1].slag = 112;
for(int i = 0; i < 2; i++){
cout << "#" << i + 1 << ":" << endl;
cout << "dross:" << ch[i].dross << endl;
cout << "slag:" << ch[i].slag << endl;
}
return 0;
}4。请基于下面这个名称空间编写一个由3个文件组成的程序：
namespace SALES
{
const int QUARTERS = 4;
struct Sales
{
double sales [QUARTERS];
double average;
double max;
double min;
};
// copies the lesser of 4 or n items from the array ar
// to the sales member of s and computes and stores the
// average, maximum, and minimum values of the entered items;
// remaining elements of sales ,if any, set to 0
void setSales(Sales & s,const double ar[],int n);
// gathers sales for 4 quarters interactively,stores them
// in the sales member of s and computes and stores the
// average,maximum,and minimum values
void setSales (Sales & s);
// display all information in structure s
void showSales(const Sales & s);
}
第一个文件是一个头文件，其中包含名称空间：第二个文件是一个源代码文件，它对这个名称空间进行扩展，以提供这三个函数的定义；第三个文件声明两个Sales对象，并使用setSales（）的交互式版本为一个结构提供值，然后使用setSales（）的非交互式版本为另一个结构提供值。另外它还使用showSales（）来显示这两个结构的内容。
//sales.h-----头文件
namespace SALES
{
const int QUARTERS = 4;
struct Sales
{
double sales [QUARTERS];
double average;
double max;
double min;
};
void setSales(Sales & s,const double ar[],int n);
void setSales (Sales & s);
void showSales(const Sales & s);
}//sales.cpp-----源代码文件
#include "sales.h"
using namespace std;
namespace SALES
{
void setSales(Sales &s, const double ar[], int n)
{
double min = 0, max = 0, sum = 0;
s.min = s.max = ar[0];
for (int i = 0; i < n; i++)
{
s.sales[i] = ar[i];
sum += ar[i];
if (ar[i] > max)
{
max = ar[i];
}
if (ar[i] < min)
{
min = ar[i];
}
}
s.average = sum / n;
}
void setSales(Sales &s)
{
cout << "Please enter 4 quarters for sales:" << endl;
cout << "the 1 quarter :";
cin >> s.sales[0];
s.min = s.max = s.sales[0];
for (int i = 1; i < 4; i++)
{
cout << "the " << i << " quarter :";
cin >> s.sales[i];
if (s.max < s.sales[i])
{
s.max = s.sales[i];
}
if (s.min > s.sales[i])
{
s.min = s.sales[i];
}
}
s.average = (s.sales[0] + s.sales[1] + s.sales[2] + s.sales[3]) / 4;
}
void showSales(const Sales &s)
{
cout << "Display all information in sales : " << endl;
cout << "The 4 quarters are $" << s.sales[0] << ", $" << s.sales[1] << ", $" << s.sales[2] << ", $" << s.sales[3] << endl;
cout << "The average income is $" << s.average << endl;
cout << "The maximum income is $" << s.max << endl;
cout << "The minimum income is $" << s.min << endl;
}
}//main.cpp
#include "sales.h"
#include <iostream>
using namespace SALES;
int main()
{
double arr[4] = {3.4, 5.6, 2.5, 6.1};
Sales s1, s2;
setSales(s1, arr, 4);
showSales(s1);
setSales(s2);
showSales(s2);
return 0;
}