[C++ Primer Plus] 第8章、函数探幽（二）课后习题

#include <iostream>  
usingnamespace std;

void show(constchar * a, int b = 0);//默认b为0void show(constchar * a, int b)
{
    staticint uses = 0;
    int lim = ++uses;
    cout << ",第" << uses << "次调用.\n";
    if (b == 0)
        lim = 1;
    for (int i = 0; i<lim; i++)
        cout << a<< endl;
}
void main()
{
    int i;
    constchar * p = "hello world";
    cout << "输入函数调用次数:";
    cin >> i;
    while (i >= 0)
    {
        cout << "参数n为:" << i;
        show(p, i);
        i--;
    }
    cout << "默认n为0:";
    show(p);
    system("pause");
}

#include <iostream>  
usingnamespace std;

struct CandyBar {
    char brand[50];
    double weight;
    int energy;
};

void fun(CandyBar &cb, char *p = "Mill Munch", double w = 2.85, int e = 350) {
    strcpy(cb.brand,p); //字符串拷贝,字符串不能直接使用赋值号
    cb.weight = w;
    cb.energy = e;
}
void show(const CandyBar &cb) {
    cout << cb.brand << endl;
    cout << cb.weight<< endl;
    cout << cb.energy<< endl;
}

void main()
{
    CandyBar haha;
    fun(haha, "gua wa zi", 3.75);
    show(haha);
    system("pause");
}

#include <iostream>  
#include <string>  
usingnamespace std;

void toBig(string &s) {
    int i = 0;
    while (s[i])
    {
        s[i] = toupper(s[i]);
        i++;
    }
}

void main()
{
    string str;
    cout << "Enter a string (q to quit):";
    getline(cin, str);
    while (str != "q") {
        toBig(str);
        cout << str << endl;
        cout << "Next string (q to quit):";
        getline(cin, str);
    }
    cout << "Bye." << endl;
    system("pause");
}

#include <iostream>  
#include <cstring>  //for strlen(),strcpy()usingnamespace std;

struct stringy {
    char *str;
    int ct;
};

voidset(stringy &s, constchar *str);
void show(constchar *str, constint count = 1);
void show(const stringy &s, constint count = 1);

void 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!");
    system("pause");
}

voidset(stringy &s, constchar *str)
{
    int len = strlen(str);
    s.ct = len;
    s.str = newchar(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(constchar *str, constint count)
{
    for (int i = 0; i < count; ++i)
        cout << str << endl;
}

void show(const stringy &s, constint count)
{
    for (int i = 0; i < count; ++i)
        cout << s.str << endl;
}

#include <iostream>  
usingnamespace std;

template<typename T>
T max5(T t[5]) {
    T m=t[0];
    for (int i = 1; i < 5; i++)
    {
        if (t[i] > m)
            m = t[i];
    }
    return m;
}

void main()
{
    int n[] = { 1,8,10,6,3 };
    double m[] = { 5.0,2.0,7.0,3.0,7.1 };
    cout << max5(n) << endl;
    cout << max5(m) << endl;
    system("pause");
}

#include <iostream>  
#include <cstring>  
usingnamespace std;

template<typename T>
T maxn(T t[],int n) {
    T m=t[0];
    for (int i = 1; i < n; i++)
    {
        if (t[i] > m)
            m = t[i];
    }
    return m;
}
//模板具体化
template <> char * maxn<char *>(char *arr[], int n) {
    int len = strlen(arr[0]);
    char *p = arr[0];
    for (int i = 1; i < n; i++)
    {
        if (strlen(arr[i]) > len) {
            p = arr[i];
            len = strlen(arr[i]);
        }
    }
    return p;
}

void main()
{
    int n[] = { 1,8,10,6,30,7 };
    double m[] = { 5.0,2.0,7.2,3.0};
    cout << maxn(n,6) << endl;
    cout << maxn(m,4) << endl;

    char *str[] = {    "asd","asdf","asdfg","asdfgh","asdfop"};
    cout << maxn(str, 5) << endl;
    system("pause");
}

#include <iostream>   
usingnamespace std;

template <typename T>
T SumArray(T arr[], int n) {
    cout << "template A" << endl;
    T sum = 0;
    for (int i = 0; i < n; i++)
        sum+=arr[i];
    return sum;
}
template <typename T>
T SumArray(T * arr[], int n) {//指针数组:[]比*优先级高
    cout << "template B" << endl;
    T sum = 0;
    for (int i = 0; i < n; i++)
        sum += *arr[i];
    return sum;
}

struct debt {
    char name[40];
    double amount;
};

void main()
{
    int thing[6] = { 13,31,103,301,310,130 };
    struct debt mr_E[3] = {
        { "I W",2400.0 },
        { "U F",1300.0 },
        { "I S",1800.0 }
    };
    double *pd[3];
    for (int i = 0; i < 3; i++)
        pd[i] = &mr_E[i].amount;
    cout << "Listen:" << endl;
    cout <<SumArray(thing, 6)<<endl;
    cout << "Listen debts:" << endl;
    cout << SumArray(pd, 3)<<endl;

    system("pause");
}