C++ Primer Plus第8章题目题解

C++ Primer Plus第8章题目题解

#include   

void PrintStr(char *str, int flag = 0);

int main()
{
	char str[] = "fuck fuck fuck";
	std::cout << "#1 " << std::endl;
	PrintStr(str);
	std::cout << "#2 " << std::endl;
	PrintStr(str, 1996);
	std::cout << "#3 " << std::endl;
	PrintStr(str, 1996);
	std::cout << "#4 " << std::endl;
	PrintStr(str);
	return 0;
}

void PrintStr(char *str, int flag)
{
	static int count = 0;                 //无连接性静态变量只初始化一次且始终存在
	++count;
	if (!flag)
		std::cout << str << std::endl;
	else
	for (int i = 0; i < count; ++i)
		std::cout << str << std::endl;
}

8-2

#include   
#include   

struct CandyBar
{
	char name[30];
	double weight;
	int heat;
};

void setCandyBar(CandyBar &c, const char *s = "Millennium Munch", const double w = 2.85, const int h = 350);
void disp(const CandyBar &c);

int main()
{
	CandyBar c;
	setCandyBar(c);
	disp(c);
	char name[30];
	double weight;
	int heat;
	std::cin.getline(name, 30);
	std::cin >> weight >> heat;
	setCandyBar(c, name, weight, heat);
	disp(c);
	return 0;
}

void setCandyBar(CandyBar &c, const char *s, const double w, const int h)
{
	strcpy(c.name, s);
	c.weight = w;
	c.heat = h;
}

void disp(const CandyBar &c)
{
	std::cout << c.name << std::endl << c.weight << std::endl << c.heat << std::endl;
}

8-3

#include   
#include   
  
void changeUpper(std::string &s);  
  
int main()  
{  
    std::string s;  
    while(getline(std::cin, s) && s[0] != 'q')  
    {  
        changeUpper(s);  
        std::cout << s << std::endl;  
    }  
    return 0;  
}  
  
void changeUpper(std::string &s)  
{  
    for(int i = 0; i < s.size(); ++i)  
        s[i] = toupper(s[i]);  
}  

8-4

#include   
#include   
  
struct stringy{  
    char *str;  
    int ct;  
};  
  
void set(stringy &s, const char *str);  
void show(const char *str, const int count = 1);  
void show(const stringy &s, const int count = 1);  
  
int main()  
{  
    stringy beany;  
    char testing[] = "Reality isn't what it used to be.";  
  
    set(beany, testing);  
    show(beany);  
    show(beany, 2);  
    testing[0] = 'D';  
    testing[1] = 'u';  
    show(testing);  
    show(testing, 3);  
    show("Done!");  
    return 0;  
}  
  
void set(stringy &s, const char *str)  
{  
    int len = strlen(str);  
    s.ct = len;  
    s.str = new char(len + 1); //要留一个字符存放'\0' 所以分配len + 1空间  
    strcpy(s.str, str);  
}  
  
void show(const char *str, const int count)  
{  
    for(int i = 0 ; i < count ; ++i)  
        std::cout << str << std::endl;  
}  
  
void show(const stringy &s, const int count)  
{  
    for(int i = 0 ;i < count ; ++i)  
        std::cout << s.str << std::endl;  
}  

8-5

#include   
  
template   
T max5(T *a);  
  
int main()  
{  
    int a[5] = {2, 3, 1, 5, 4};  
    double b[5] = {1.1, 3.3, 5.5, 4.4, 2.2};  
    std::cout << max5(a) << std::endl;  
    std::cout << max5(b) << std::endl;  
    return 0;  
}  
  
template   
T max5(T *a)  
{  
    T max = -1;  
    for(int i = 0 ;i < 5 ; ++i)  
        max = max < a[i] ? a[i] : max;  
    return max;  
}  

8-6

#include   
#include   
  
template   
T maxn(T *a, int len);  
  
template <> char *maxn(char *a[], int len);  
  
int main()  
{  
    int a[6] = {1, 2, 3, 4, 5, 6};  
    double b[4] = {1.1, 2.2, 3.3, 4.4};  
    char *c[5] = {"fuck", "fuckfuck", "fuckfuckfuck", "fuckfuckfuckfuck", "fuckfuckfuckfuckfuck"};  
    std::cout << maxn(a, 6) << std::endl;  
    std::cout << maxn(b, 4) << std::endl;  
    std::cout << maxn(c, 5) << std::endl;  
    return 0;  
}  
  
template   
T maxn(T *a, int len)  
{  
    T max = -1;  
    for(int i = 0 ; i < len ; ++i)  
        max = max < a[i] ? a[i] : max;  
    return max;  
}  
  
template <> char *maxn(char *a[], int len)  
{  
    int max = -1;  
    char *p = NULL;  
    for(int i = 0 ; i < len ; ++i)  
    {  
        if((int)strlen(a[i])> max)  
        {  
            max = strlen(a[i]);  
            p = a[i];  
        }  
    }  
    return p;  
}  

8-7

#include   
  
struct debts  
{  
    char name[50];  
    double amount;  
};  
  
template   
T SumArray(T a[], int n);  
  
template   
T SumArray(T *a[], int n);  
  
int main()  
{  
    int things[6] = {13, 31, 103, 301, 310, 130};  
    debts mr_E[3] = {  
        {"Ima Wolfe", 2400.0},  
        {"Ura Foxe", 1300.0},  
        {"Iby Stout", 1800.0}  
    };  
    double * pd[3];  
    for(int i = 0 ; i < 3 ; ++i)  
        pd[i] = &mr_E[i].amount;  
    std::cout << SumArray(things, 6) << std::endl;  
    std::cout << SumArray(pd, 3) << std::endl;  
    return 0;  
}  
  
template   
T SumArray(T a[], int n)  
{  
    T sum = 0 ;  
    for(int i = 0 ; i < n ; ++i)  
        sum += a[i];  
    return sum;  
}  
  
template   
T SumArray(T *a[], int n)  
{  
    T sum = 0;  
    for(int i = 0 ; i < n ; ++i)  
        sum += *a[i];  
    return sum;  
}